Method for transmitting dmrs for pscch in connection with nr v2x, and synchronization

ABSTRACT

A method for performing wireless communication by a first device is proposed in an embodiment. The method may comprise the steps of: selecting a synchronization source on the basis of a sidelink synchronization priority; acquiring synchronization on the basis of the synchronization source; transmitting a sidelink-synchronization signal block (S-SSB) to a second device on the basis of the acquired synchronization; transmitting, to the second device, information related to a pattern of a physical sidelink shared channel (PSSCH) demodulation reference signal (DMRS) for decoding a PSSCH through sidelink control information (SCI) on a physical sidelink control channel (PSCCH); mapping the PSSCH DMRS onto a time resource related to the PSSCH on the basis of the information related to the pattern of the SSCH DMRS and an interval of a time resource scheduled for transmission of the PSSCH related to the PSCCH; and transmitting the PSSCH DMRS to the second device through the PSSCH.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

This disclosure relates to a wireless communication system.

Related Art

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic.

Vehicle-to-everything (V2X) refers to a communication technology throughwhich a vehicle exchanges information with another vehicle, apedestrian, an object having an infrastructure (or infra) establishedtherein, and so on. The V2X may be divided into 4 types, such asvehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (MTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR. Theembodiment of FIG. 1 may be combined with various embodiments of thepresent disclosure.

Regarding V2X communication, a scheme of providing a safety service,based on a V2X message such as Basic Safety Message (BSM), CooperativeAwareness Message (CAM), and Decentralized Environmental NotificationMessage (DENM) is focused in the discussion on the RAT used before theNR. The V2X message may include position information, dynamicinformation, attribute information, or the like. For example, a UE maytransmit a periodic message type CAM and/or an event triggered messagetype DENM to another UE.

For example, the CAM may include dynamic state information of thevehicle such as direction and speed, static data of the vehicle such asa size, and basic vehicle information such as an exterior illuminationstate, route details, or the like. For example, the UE may broadcast theCAM, and latency of the CAM may be less than 100 ms. For example, the UEmay generate the DENM and transmit it to another UE in an unexpectedsituation such as a vehicle breakdown, accident, or the like. Forexample, all vehicles within a transmission range of the UE may receivethe CAM and/or the DENM. In this case, the DENM may have a higherpriority than the CAM.

Thereafter, regarding V2X communication, various V2X scenarios areproposed in NR. For example, the various V2X scenarios may includevehicle platooning, advanced driving, extended sensors, remote driving,or the like.

For example, based on the vehicle platooning, vehicles may move togetherby dynamically forming a group. For example, in order to perform platoonoperations based on the vehicle platooning, the vehicles belonging tothe group may receive periodic data from a leading vehicle. For example,the vehicles belonging to the group may decrease or increase an intervalbetween the vehicles by using the periodic data.

For example, based on the advanced driving, the vehicle may besemi-automated or fully automated. For example, each vehicle may adjusttrajectories or maneuvers, based on data obtained from a local sensor ofa proximity vehicle and/or a proximity logical entity. In addition, forexample, each vehicle may share driving intention with proximityvehicles.

For example, based on the extended sensors, raw data, processed data, orlive video data obtained through the local sensors may be exchangedbetween a vehicle, a logical entity, a UE of pedestrians, and/or a V2Xapplication server. Therefore, for example, the vehicle may recognize amore improved environment than an environment in which a self-sensor isused for detection.

For example, based on the remote driving, for a person who cannot driveor a remote vehicle in a dangerous environment, a remote driver or a V2Xapplication may operate or control the remote vehicle. For example, if aroute is predictable such as public transportation, cloud computingbased driving may be used for the operation or control of the remotevehicle. In addition, for example, an access for a cloud-based back-endservice platform may be considered for the remote driving.

Meanwhile, a scheme of specifying service requirements for various V2Xscenarios such as vehicle platooning, advanced driving, extendedsensors, remote driving, or the like is discussed in NR-based V2Xcommunication.

SUMMARY OF THE DISCLOSURE Technical Objects

Meanwhile, in order to increase a usage efficiency of resources fordata, for the NR system, a form in which resources for a physicalsidelink control channel (PSCCH) are superimposed on resources for aphysical sidelink shared channel (PSSCH) or a form in which resourcesfor a PSCCH are surrounded by resources for a PSSCH may be supported.

In this case, for example, when a length of a symbol duration of thePSCCH is relatively larger than a length of a symbol duration of acontrol resource set (CORESET) for a downlink, if the transmittingterminal does not map a PSSCH demodulation reference signal (DMRS) inthe PSSCH resources of the frequency division multiplexing (FDM) areawith the PSCCH, the PSSCH detection performance of the receivingterminal may be deteriorated. In addition, for example, when the PSCCHand the PSSCH are time division multiplexing (TDM), if PSSCH DMRS is notmapped after resources related to the PSCCH, it may cause deteriorationof the detection performance of the receiving terminal for the PSSCH.

Technical Solutions

According to an embodiment of the present disclosure, there is provideda method of performing wireless communication by a first device. Themethod may include selecting a synchronization source based on asidelink synchronization priority, wherein the synchronization sourceincludes at least one of a global navigation satellite system (GNSS), abase station, or a terminal, obtaining synchronization based on thesynchronization source, transmitting, to a second device, asidelink-synchronization signal block (S-SSB) block based on thesynchronization, wherein the S-SSB block may include a sidelink primarysynchronization signal (S-PSS), a sidelink secondary synchronizationsignal (S-SSS), and a physical sidelink broadcast channel (PSBCH),transmitting, to the second device, information related to a pattern ofa physical sidelink shared channel demodulation reference signal (PSSCHDMRS) for decoding a PSSCH through a sidelink control information (SCI)on a physical sidelink control channel (PSCCH), mapping the PSSCH DMRSto time resources related to the PSSCH based on the information relatedto the pattern of the PSSCH DMRS and a duration of time resourcesscheduled for transmission of the PSSCH related to the PSCCH,transmitting, to the second device through the PSSCH, the PSSCH DMRS.

Effects of the Disclosure

A UE may effectively perform sidelink communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR.

FIG. 2 shows a structure of an NR system, in accordance with anembodiment of the present disclosure.

FIG. 3 shows a functional division between an NG-RAN and a 5GC, inaccordance with an embodiment of the present disclosure.

FIG. 4 shows a radio protocol architecture, in accordance with anembodiment of the present disclosure.

FIG. 5 shows a structure of an NR system, in accordance with anembodiment of the present disclosure.

FIG. 6 shows a structure of a slot of an NR frame, in accordance with anembodiment of the present disclosure.

FIG. 7 shows an example of a BWP, in accordance with an embodiment ofthe present disclosure.

FIG. 8 shows a radio protocol architecture for a SL communication, inaccordance with an embodiment of the present disclosure.

FIG. 9 shows a UE performing V2X or SL communication, in accordance withan embodiment of the present disclosure.

FIG. 10 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, in accordance with an embodiment of thepresent disclosure.

FIG. 11 shows three cast types, in accordance with an embodiment of thepresent disclosure.

FIG. 12 shows a synchronization source or synchronization reference ofV2X based on an embodiment of the present disclosure.

FIG. 13 shows an example of resource allocation for a data channel or acontrol channel based on an embodiment of the present disclosure.

FIG. 14 shows an example of a symbol related to a sidelink in a sidelinkslot according to an embodiment of the present disclosure.

FIG. 15 shows an example of a mapping type A and a mapping type B of aPDSCH or a PUSCH according to an embodiment of the present disclosure.

FIG. 16 shows an example of a region in which FDM is performed on aPSCCH and a PSSCH according to an embodiment of the present disclosure.

FIG. 17 shows a procedure in which a transmitting terminal that hasdetermined and/or allocated resources for a PSSCH DMRS performs sidelinkcommunication with a receiving terminal, according to an embodiment ofthe present disclosure.

FIG. 18 shows an example in which a DMRS is mapped to PUSCH resourcesaccording to an embodiment of the present disclosure.

FIG. 19 shows an example in which resources related to a PSSCH aredivided into two RB groups or sub-channel groups according to anembodiment of the present disclosure.

FIG. 20 shows a case in which a transient period exists between a symbolduration in an area in which a PSCCH and a PSSCH are frequency divisionmultiplexed to each other and a symbol duration in an area in which onlya PSSCH is transmitted according to an embodiment of the presentdisclosure.

FIG. 21 shows a procedure in which a transmitting terminal transmits aDMRS to a receiving terminal through a PSSCH according to an embodimentof the present disclosure.

FIG. 22 shows a method in which a first device transmits a PSSCH DMRS toa second device through a PSSCH according to an embodiment of thepresent disclosure.

FIG. 23 shows a method for a second device to receive a PSSCH DMRS froma first device according to an embodiment of the present disclosure.

FIG. 24 shows a method in which a first device transmits a DMRS to asecond device through a PSSCH according to an embodiment of the presentdisclosure.

FIG. 25 shows a communication system 1, in accordance with an embodimentof the present disclosure.

FIG. 26 shows wireless devices, in accordance with an embodiment of thepresent disclosure.

FIG. 27 shows a signal process circuit for a transmission signal, inaccordance with an embodiment of the present disclosure.

FIG. 28 shows a wireless device, in accordance with an embodiment of thepresent disclosure.

FIG. 29 shows a hand-held device, in accordance with an embodiment ofthe present disclosure.

FIG. 30 shows a car or an autonomous vehicle, in accordance with anembodiment of the present disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the present specification, “A or B” may mean “only A”, “only B” or“both A and B.” In other words, in the present specification, “A or B”may be interpreted as “A and/or B”. For example, in the presentspecification, “A, B, or C” may mean “only A”, “only B”, “only C”, or“any combination of A, B, C”.

A slash (/) or comma used in the present specification may mean“and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B”may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C”may mean “A, B, or C”.

In the present specification, “at least one of A and B” may mean “onlyA”, “only B”, or “both A and B”. In addition, in the presentspecification, the expression “at least one of A or B” or “at least oneof A and/or B” may be interpreted as “at least one of A and B”.

In addition, in the present specification, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present specification may mean“for example”. Specifically, when indicated as “control information(PDCCH)”, it may mean that “PDCCH” is proposed as an example of the“control information”. In other words, the “control information” of thepresent specification is not limited to “PDCCH”, and “PDDCH” may beproposed as an example of the “control information”. In addition, whenindicated as “control information (i.e., PDCCH)”, it may also mean that“PDCCH” is proposed as an example of the “control information”.

A technical feature described individually in one figure in the presentspecification may be individually implemented, or may be simultaneouslyimplemented.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRA is part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

FIG. 2 shows a structure of an NR system, in accordance with anembodiment of the present disclosure. The embodiment of FIG. 2 may becombined with various embodiments of the present disclosure.

Referring to FIG. 2, a next generation-radio access network (NG-RAN) mayinclude a BS 20 providing a UE 10 with a user plane and control planeprotocol termination. For example, the BS 20 may include a nextgeneration-Node B (gNB) and/or an evolved-NodeB (eNB). For example, theUE 10 may be fixed or mobile and may be referred to as other terms, suchas a mobile station (MS), a user terminal (UT), a subscriber station(SS), a mobile terminal (MT), wireless device, and so on. For example,the BS may be referred to as a fixed station which communicates with theUE 10 and may be referred to as other terms, such as a base transceiversystem (BTS), an access point (AP), and so on.

The embodiment of FIG. 2 exemplifies a case where only the gNB isincluded. The BSs 20 may be connected to one another via Xn interface.The BS 20 may be connected to one another via 5th generation (5G) corenetwork (5GC) and NG interface. More specifically, the BSs 20 may beconnected to an access and mobility management function (AMF) 30 viaNG-C interface, and may be connected to a user plane function (UPF) 30via NG-U interface.

FIG. 3 shows a functional division between an NG-RAN and a 5GC, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 3, the gNB may provide functions, such as Inter CellRadio Resource Management (RRM), Radio Bearer (RB) control, ConnectionMobility Control, Radio Admission Control, Measurement Configuration &Provision, Dynamic Resource Allocation, and so on. An AMF may providefunctions, such as Non Access Stratum (NAS) security, idle statemobility processing, and so on. A UPF may provide functions, such asMobility Anchoring, Protocol Data Unit (PDU) processing, and so on. ASession Management Function (SMF) may provide functions, such as userequipment (UE) Internet Protocol (IP) address allocation, PDU sessioncontrol, and so on.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of the open systeminterconnection (OSI) model that is well-known in the communicationsystem. Among them, a physical (PHY) layer belonging to the first layerprovides an information transfer service by using a physical channel,and a radio resource control (RRC) layer belonging to the third layerserves to control a radio resource between the UE and the network. Forthis, the RRC layer exchanges an RRC message between the UE and the BS.

FIG. 4 shows a radio protocol architecture, in accordance with anembodiment of the present disclosure. The embodiment of FIG. 4 may becombined with various embodiments of the present disclosure.Specifically, FIG. 4(a) shows a radio protocol architecture for a userplane, and FIG. 4(b) shows a radio protocol architecture for a controlplane. The user plane corresponds to a protocol stack for user datatransmission, and the control plane corresponds to a protocol stack forcontrol signal transmission.

Referring to FIG. 4, a physical layer provides an upper layer with aninformation transfer service through a physical channel. The physicallayer is connected to a medium access control (MAC) layer which is anupper layer of the physical layer through a transport channel Data istransferred between the MAC layer and the physical layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PHYlayer) and the second layer (i.e., the MAC layer, the RLC layer, and thepacket data convergence protocol (PDCP) layer) for data delivery betweenthe UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

The physical channel includes several OFDM symbols in a time domain andseveral sub-carriers in a frequency domain. One sub-frame includes aplurality of OFDM symbols in the time domain. A resource block is a unitof resource allocation, and consists of a plurality of OFDM symbols anda plurality of sub-carriers. Further, each subframe may use specificsub-carriers of specific OFDM symbols (e.g., a first OFDM symbol) of acorresponding subframe for a physical downlink control channel (PDCCH),i.e., an L1/L2 control channel A transmission time interval (TTI) is aunit time of subframe transmission.

FIG. 5 shows a structure of an NR system, in accordance with anembodiment of the present disclosure. The embodiment of FIG. 5 may becombined with various embodiments of the present disclosure.

Referring to FIG. 5, in the NR, a radio frame may be used for performinguplink and downlink transmission. A radio frame has a length of 10 msand may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined in accordance with subcarrier spacing (SCS).Each slot may include 12 or 14 OFDM(A) symbols according to a cyclicprefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot) _(symb)), a number slots per frame (N^(frame,a) _(slot)),and a number of slots per subframe (N^(subframe,u) _(slot)) based on anSCS configuration (u), in a case where a normal CP is used.

TABLE 1 SCS (15*2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot)  15 KHz (u = 0) 14 10 1  30 KHz (u = 1) 14 20 2 60 KHz (u = 2) 14 40 4 120 KHz (u = 3) 14 80 8 240 KHz (u = 4) 14 16016

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe in accordance withthe SCS, in a case where an extended CP is used.

TABLE 2 SCS (15*2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 60 KHz (u = 2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

In the NR, multiple numerologies or SCSs for supporting diverse 5Gservices may be supported. For example, in case an SCS is 15 kHz, a widearea of the conventional cellular bands may be supported, and, in casean SCS is 30 kHz/60 kHz a dense-urban, lower latency, wider carrierbandwidth may be supported. In case the SCS is 60 kHz or higher, abandwidth that is greater than 24.25 GHz may be used in order toovercome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, the two different types of frequency ranges may be as shownbelow in Table 3. Among the frequency ranges that are used in an NRsystem, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6GHz range” and may also be referred to as a millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding frequency Subcarrier Spacingdesignation range (SCS) FR1  450 MHz-6000 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, as shown below in Table 4, FR1may include a band within a range of 410 MHz to 7125 MHz. Morespecifically, FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz(or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1mat include an unlicensed band. The unlicensed band may be used fordiverse purposes, e.g., the unlicensed band for vehicle-specificcommunication (e.g., automated driving).

TABLE 4 Frequency Range Corresponding frequency Subcarrier Spacingdesignation range (SCS) FR1  410 MHz-7125 MHz 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 6 shows a structure of a slot of an NR frame, in accordance with anembodiment of the present disclosure.

Referring to FIG. 6, a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS, CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Meanwhile, a radio interface between a UE and another UE or a radiointerface between the UE and a network may consist of an L1 layer, an L2layer, and an L3 layer. In various embodiments of the presentdisclosure, the L1 layer may imply a physical layer. In addition, forexample, the L2 layer may imply at least one of a MAC layer, an RLClayer, a PDCP layer, and an SDAP layer. In addition, for example, the L3layer may imply an RRC layer.

Hereinafter, a bandwidth part (BWP) and a carrier will be described.

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier.

When using bandwidth adaptation (BA), a reception bandwidth andtransmission bandwidth of a UE are not necessarily as large as abandwidth of a cell, and the reception bandwidth and transmissionbandwidth of the BS may be adjusted. For example, a network/BS mayinform the UE of bandwidth adjustment. For example, the UE receiveinformation/configuration for bandwidth adjustment from the network/BS.In this case, the UE may perform bandwidth adjustment based on thereceived information/configuration. For example, the bandwidthadjustment may include an increase/decrease of the bandwidth, a positionchange of the bandwidth, or a change in subcarrier spacing of thebandwidth.

For example, the bandwidth may be decreased during a period in whichactivity is low to save power. For example, the position of thebandwidth may move in a frequency domain. For example, the position ofthe bandwidth may move in the frequency domain to increase schedulingflexibility. For example, the subcarrier spacing of the bandwidth may bechanged. For example, the subcarrier spacing of the bandwidth may bechanged to allow a different service. A subset of a total cell bandwidthof a cell may be called a bandwidth part (BWP). The BA may be performedwhen the BS/network configures the BWP to the UE and the BS/networkinforms the UE of the BWP currently in an active state among theconfigured BWPs.

For example, the BWP may be at least any one of an active BWP, aninitial BWP, and/or a default BWP. For example, the UE may not monitordownlink radio link quality in a DL BWP other than an active DL BWP on aprimary cell (PCell). For example, the UE may not receive PDCCH, PDSCH,or CSI-RS (excluding RRM) outside the active DL BWP. For example, the UEmay not trigger a channel state information (CSI) report for theinactive DL BWP. For example, the UE may not transmit PUCCH or PUSCHoutside an active UL BWP. For example, in a downlink case, the initialBWP may be given as a consecutive RB set for an RMSI CORESET (configuredby PBCH). For example, in an uplink case, the initial BWP may be givenby SIB for a random access procedure. For example, the default BWP maybe configured by a higher layer. For example, an initial value of thedefault BWP may be an initial DL BWP. For energy saving, if the UE failsto detect DCI during a specific period, the UE may switch the active BWPof the UE to the default BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmitan SL channel or an SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. The SL BWP may be (pre-)configured in a carrier withrespect to an out-of-coverage NR V2X UE and an RRC_IDLE UE. For the UEin the RRC_CONNECTED mode, at least one SL BWP may be activated in thecarrier.

FIG. 7 shows an example of a BWP, in accordance with an embodiment ofthe present disclosure. The embodiment of FIG. 7 may be combined withvarious embodiments of the present disclosure. It is assumed in theembodiment of FIG. 7 that the number of BWPs is 3.

Referring to FIG. 7, a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset N^(start) _(BWP) fromthe point A, and a bandwidth N^(size) _(BWP). For example, the point Amay be an external reference point of a PRB of a carrier in which asubcarrier 0 of all numerologies (e.g., all numerologies supported by anetwork on that carrier) is aligned. For example, the offset may be aPRB interval between a lowest subcarrier and the point A in a givennumerology. For example, the bandwidth may be the number of PRBs in thegiven numerology.

Hereinafter, V2X or SL communication will be described.

FIG. 8 shows a radio protocol architecture for a SL communication, inaccordance with an embodiment of the present disclosure. The embodimentof FIG. 8 may be combined with various embodiments of the presentdisclosure. More specifically, FIG. 8(a) shows a user plane protocolstack, and FIG. 8(b) shows a control plane protocol stack.

Hereinafter, a sidelink synchronization signal (SLSS) andsynchronization information will be described.

The SLSS may include a primary sidelink synchronization signal (PSSS)and a secondary sidelink synchronization signal (SSSS), as anSL-specific sequence. The PSSS may be referred to as a sidelink primarysynchronization signal (S-PSS), and the SSSS may be referred to as asidelink secondary synchronization signal (S-SSS). For example,length-127 M-sequences may be used for the S-PSS, and length-127 goldsequences may be used for the S-SSS. For example, a UE may use the S-PSSfor initial signal detection and for synchronization acquisition. Forexample, the UE may use the S-PSS and the S-SSS for acquisition ofdetailed synchronization and for detection of a synchronization signalID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS, a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit CRC.

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-)configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

FIG. 9 shows a UE performing V2X or SL communication, in accordance withan embodiment of the present disclosure. The embodiment of FIG. 9 may becombined with various embodiments of the present disclosure.

Referring to FIG. 9, in V2X or SL communication, the term ‘UE’ maygenerally imply a UE of a user. However, if a network equipment such asa BS transmits/receives a signal according to a communication schemebetween UEs, the BS may also be regarded as a sort of the UE. Forexample, a UE 1 may be a first apparatus 100, and a UE 2 may be a secondapparatus 200.

For example, the UE 1 may select a resource unit corresponding to aspecific resource in a resource pool which implies a set of series ofresources. In addition, the UE 1 may transmit an SL signal by using theresource unit. For example, a resource pool in which the UE 1 is capableof transmitting a signal may be configured to the UE 2 which is areceiving UE, and the signal of the UE 1 may be detected in the resourcepool.

Herein, if the UE 1 is within a connectivity range of the BS, the BS mayinform the UE 1 of the resource pool. Otherwise, if the UE 1 is out ofthe connectivity range of the BS, another UE may inform the UE 1 of theresource pool, or the UE 1 may use a pre-configured resource pool.

In general, the resource pool may be configured in unit of a pluralityof resources, and each UE may select a unit of one or a plurality ofresources to use it in SL signal transmission thereof.

Hereinafter, resource allocation in SL will be described.

FIG. 10 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, in accordance with an embodiment of thepresent disclosure. The embodiment of FIG. 10 may be combined withvarious embodiments of the present disclosure. In various embodiments ofthe present disclosure, the transmission mode may be called a mode or aresource allocation mode. Hereinafter, for convenience of explanation,in LTE, the transmission mode may be called an LTE transmission mode. InNR, the transmission mode may be called an NR resource allocation mode.

For example, FIG. 10(a) shows a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, FIG. 10(a) shows a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example, FIG. 10(b) shows a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, FIG. 10(b) shows a UE operation related to an NR resourceallocation mode 2.

Referring to FIG. 10(a), in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a BS mayschedule an SL resource to be used by the UE for SL transmission. Forexample, the BS may perform resource scheduling to a UE 1 through aPDCCH (more specifically, downlink control information (DCI)), and theUE 1 may perform V2X or SL communication with respect to a UE 2according to the resource scheduling. For example, the UE 1 may transmita sidelink control information (SCI) to the UE 2 through a physicalsidelink control channel (PSCCH), and thereafter transmit data based onthe SCI to the UE 2 through a physical sidelink shared channel (PSSCH).

Referring to FIG. 10(b), in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, the UE maydetermine an SL transmission resource within an SL resource configuredby a BS/network or a pre-configured SL resource. For example, theconfigured SL resource or the pre-configured SL resource may be aresource pool. For example, the UE may autonomously select or schedule aresource for SL transmission. For example, the UE may perform SLcommunication by autonomously selecting a resource within a configuredresource pool. For example, the UE may autonomously select a resourcewithin a selective window by performing a sensing and resource(re)selection procedure. For example, the sensing may be performed inunit of subchannels. In addition, the UE 1 which has autonomouslyselected the resource within the resource pool may transmit the SCI tothe UE 2 through a PSCCH, and thereafter may transmit data based on theSCI to the UE 2 through a PSSCH.

FIG. 11 shows three cast types, in accordance with an embodiment of thepresent disclosure. The embodiment of FIG. 11 may be combined withvarious embodiments of the present disclosure. Specifically, FIG. 11(a)shows broadcast-type SL communication, FIG. 11(b) shows unicast type-SLcommunication, and FIG. 11(c) shows groupcast-type SL communication. Incase of the unicast-type SL communication, a UE may perform one-to-onecommunication with respect to another UE. In case of the groupcast-typeSL transmission, the UE may perform SL communication with respect to oneor more UEs in a group to which the UE belongs. In various embodimentsof the present disclosure, SL groupcast communication may be replacedwith SL multicast communication, SL one-to-many communication, or thelike.

Meanwhile, in order to increase a usage efficiency of resources fordata, for the NR system, a form in which resources for a PSCCH aresuperimposed on resources for a PSSCH or a form in which resources for aPSCCH are surrounded by resources for a PSSCH may be supported.

FIG. 12 shows a synchronization source or synchronization reference ofV2X based on an embodiment of the present disclosure. The embodiment ofFIG. 12 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 12, in V2X, a UE may be directly synchronized with aglobal navigation satellite system (GNSS), or may be indirectlysynchronized with the GNSS through a UE (inside network coverage oroutside network coverage) directly synchronized with the GNSS. If theGNSS is configured as the synchronization source, the UE may calculate aDFN and a subframe number by using a coordinated universal time (UTC)and a (pre-)configured direct frame number (DFN) offset.

Alternatively, the UE may be directly synchronized with a BS, or may besynchronized with another UE which is time/frequency-synchronized withthe BS. For example, the BS may be an eNB or a gNB. For example, if theUE is inside the network coverage, the UE may receive synchronizationinformation provided by the BS, and may be directly synchronized withthe BS. Thereafter, the UE may provide the synchronization informationto adjacent another UE. If BS timing is configured based onsynchronization, for synchronization and downlink measurement, the UEmay be dependent on a cell related to a corresponding frequency (when itis inside the cell coverage at the frequency), or a primary cell or aserving cell (when it is outside the cell coverage at the frequency).

The BS (e.g., serving cell) may provide a synchronization configurationfor a carrier used in V2X or SL communication. In this case, the UE mayconform to the synchronization configuration received from the BS. Ifthe UE fails to detect any cell in a carrier used in the V2X or SLcommunication and fails to receive the synchronization configurationfrom the serving cell, the UE may conform to a pre-configuredsynchronization configuration.

Alternatively, the UE may be synchronized with another UE which fails toobtain synchronization information directly or indirectly from the BS orthe GNSS. A synchronization source or preference may be pre-configuredto the UE. Alternatively, the synchronization source and preference maybe configured through a control message provided by the BS.

An SL synchronization source may be associated/related with asynchronization priority. For example, a relation between thesynchronization source and the synchronization priority may be definedas shown in Table 5 or Table 6. Table 5 or Table 6 are for exemplarypurposes only, and the relation between the synchronization source andthe synchronization priority may be defined in various forms.

TABLE 5 Priority eNB/gNB-based level GNSS-based synchronizationsynchronization P0 GNSS BS P1 All UEs directly synchronized All UEsdirectly with GNSS synchronized with BS P2 All UEs indirectlysynchronized All UEs indirectly with GNSS synchronized with BS P3 Allother UEs GNSS P4 N/A All UEs directly synchronized with GNSS P5 N/A AllUEs indirectly synchronized with GNSS P6 N/A All other UEs

TABLE 6 Priority eNB/gNB-based level GNSS-based synchronizationsynchronization P0 GNSS BS P1 All UEs directly synchronized All UEsdirectly with GNSS synchronized with BS P2 All UEs indirectlysynchronized All UEs indirectly with GNSS synchronized with BS P3 BSGNSS P4 All UEs directly synchronized All UEs directly with BSsynchronized with GNSS P5 All UEs indirectly synchronized All UEsindirectly with BS synchronized with GNSS P6 Remaining UE(s) having lowRemaining UE(s) having priority low priority

In Table 5 or Table 6, PO may denote a highest priority, and P6 maydenote a lowest priority. In Table 5 or Table 6, the BS may include atleast one of a gNB and an eNB.

Whether to use GNSS-based synchronization or BS-based synchronizationmay be (pre-)configured. In a single-carrier operation, the UE mayderive transmission timing of the UE from an available synchronizationreference having the highest priority.

Meanwhile, in order to increase a usage efficiency of resources fordata, for the NR system, a form in which resources for a PSCCH aresuperimposed on resources for a PSSCH or a form in which resources for aPSCCH are surrounded by resources for a PSSCH may be supported.

FIG. 13 shows an example of resource allocation for a data channel or acontrol channel based on an embodiment of the present disclosure. Theembodiment of FIG. 13 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 13, resources for a control channel (e.g., PSCCH) maybe allocated to the UE in a form (#S1, #S2, #S3) superimposed onresources for a data channel (e.g., PSSCH). Alternatively, resources fora control channel (e.g., PSCCH) may be allocated to the UE in a form(#S4) surrounded by resources for a data channel (e.g., PSSCH).

Meanwhile, the UE may map a DMRS related to a PSSCH or a DMRS fordecoding a PSSCH into resources allocated for the PSSCH. For example,the corresponding DMRS may be mapped so as not to overlap with aposition of a resource to which the PSCCH is mapped according to amultiplexing scheme of the PSCCH and the PSSCH. For example, thecorresponding DMRS may be mapped to a PUSCH resource region so as not tooverlap with a position of a resource to which the PSCCH is mappedaccording to a multiplexing scheme of the PSCCH and the PSSCH.

FIG. 14 shows an example of a symbol related to a sidelink in a sidelinkslot according to an embodiment of the present disclosure. Theembodiment of FIG. 14 may be combined with various embodiments of thepresent disclosure.

A size of a sidelink resource (e.g., the number of symbols capable of SLtransmission/reception in one slot) may be different between slots. Forexample, as a flexible slot format is supported in NR, the size of thesidelink resource may vary between slots. Accordingly, sidelinkresources of different sizes for each slot may be allocated to the UE.

For example, referring to FIG. 14, there may be 7 symbols capable ofsidelink communication on a SL slot #N, whereas there may be 3 symbolscapable of sidelink communication on a SL slot #N+P. Accordingly, aresource allocation method for a PSSCH and/or a mapping position ormethod of a DMRS related to the PSSCH may vary. In this specification,for convenience of description, a DMRS related to a PSSCH or a DMRS fordecoding a PSSCH may be referred to as a PSSCH DMRS. Similarly, a DMRSrelated to a PDSCH or a DMRS for decoding a PDSCH may be referred to asa PDSCH DMRS, and a DMRS related to a PUSCH or a DMRS for decoding aPUSCH may be referred to as a PUSCH DMRS.

Similarly, in the NR system, the number of symbols or a length of asymbol duration for transmission of a downlink PDSCH and an uplink PUSCHmay vary. Accordingly, a position or configuration of a resource throughwhich the DMRS is transmitted may be different according to the lengthof the symbol duration.

FIG. 15 shows an example of a mapping type A and a mapping type B of aPDSCH or a PUSCH according to an embodiment of the present disclosure.The embodiment of FIG. 15 may be combined with various embodiments ofthe present disclosure.

Referring to FIG. 15, for example, in a case of PDSCH mapping type A orPUSCH mapping type A, the PDSCH DMRS or PUSCH DMRS may be mapped to aspecific position (e.g., a symbol corresponding to symbol index 2 or 3)based on a slot boundary (e.g., a start point of a slot). And, in thecase of PDSCH mapping type A or PUSCH mapping type A, there may be arestriction in that a start symbol of the PDSCH resource must bedetermined so that the PDSCH resource includes a symbol to which thePDSCH DMRS is mapped, and there may be a restriction in that a startsymbol of the PUSCH resource must be determined so that the PUSCHresource includes a symbol to which the PUSCH DMRS is mapped.

For example, in a case of PDSCH mapping type B or PUSCH mapping type B,the PDSCH DMRS or PUSCH DMRS may be mapped to a start symbol of thePDSCH resource allocated for data transmission or a start symbol of thePUSCH resource allocated for data transmission, or the PDSCH DMRS orPUSCH DMRS may be mapped to a specific position based on the startsymbol of the PDSCH resource or the start symbol of the PUSCH resource.And, in the case of PDSCH mapping type B or PUSCH mapping type B, sincethe PDSCH DMRS and the PUSCH DMRS are each mapped to a first symbol ofthe allocated PDSCH resources or a first symbol of the allocated PUSCHresources, the restrictions on the start symbol of the PDSCH resource orthe start symbol of the PUSCH resource may be relatively less comparedto the PDSCH mapping type A or the PUSCH mapping type A. For example, inPDSCH mapping type B, a possible length of a PDSCH symbol duration maybe limited to 2, 4, or 7 symbols (6 symbols in the case of extended CP).The embodiment of FIG. 15 shows a case in which the length of a PDSCHsymbol duration is 4 symbols in PDSCH mapping type B.

In addition, for example, if the PDSCH resources allocated in PDSCHmapping type B overlaps with resources reserved for a search spacerelated to a specific control resource set (CORESET), the first PDSCHDMRS may be reconfigured to be mapped to a symbol immediately followingthe corresponding CORESET. This method of reconfiguration the mappingposition of the PDSCH DMRS may be equally applied even if the allocatedPDSCH resources partially overlap CORESET in the frequency domain. Here,for example, CORESET may be a set of time-frequency resources (e.g., aset of at least one resource block and at least one symbol) used fortransmitting a DCI through the PDCCH. For example, the CORESET may betransmitted using a portion of a channel bandwidth.

Meanwhile, for example, when a transmitting UE transmits a PSSCH to areceiving UE, in a first symbol of the PSSCH resources, the receiving UEmay perform an automatic gain control (AGC) operation. Therefore, whenthe receiving UE uses the first symbol of the PSSCH resources for AGCoperation, if the transmitting UE maps the PSSCH DMRS to the firstsymbol of the PSSCH resources, the PSSCH detection performance of thereceiving UE may decrease.

In addition, for example, as in the embodiment of FIG. 13, the PSCCH maybe allocated and/or transmitted in a superimposed form on the PSSCHresources. Meanwhile, a length of a symbol duration of the PSCCH may berelatively larger than a length of a symbol duration of the CORESET fora downlink. In this case, if the transmitting UE does not map the PSSCHDMRS in the PSSCH resource of the PSCCH and FDM (Frequency DivisionMultiplexing) area, the transmitting UE does not map the PSSCH DMRS inthe PSSCH resources of the frequency division multiplexing (FDM) areawith the PSCCH, the PSSCH detection performance of the receiving UE maybe deteriorated.

FIG. 16 shows an example of a region in which FDM is performed on aPSCCH and a PSSCH according to an embodiment of the present disclosure.The embodiment of FIG. 16 may be combined with various embodiments ofthe present disclosure.

Referring to FIG. 16, a FDM region indicates a region in which FDM isperformed for the PSCCH within PSSCH resources. The transmitting UEneeds to map a PSSCH DMRS to the resources of the FDM region in order toprevent the receiving UE from deteriorating a detection performance ofthe PSSCH. That is, in sidelink communication, in order for thetransmitting UE to efficiently transmit data to the receiving UE, thetransmitting UE needs to determine resources for a PSSCH and/orresources for mapping a PSSCH DMRS. Hereinafter, a method fordetermining resources for mapping a PSSCH DMRS and an apparatussupporting the same will be described according to various embodimentsof the present disclosure.

FIG. 17 shows a procedure in which a transmitting UE that has determinedand/or allocated resources for a PSSCH DMRS performs sidelinkcommunication with a receiving UE, according to an embodiment of thepresent disclosure. The embodiment of FIG. 17 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 17, in step S1710, the transmitting UE may determineand/or allocate resources for a PSCCH.

According to an embodiment of the present disclosure, the transmittingUE may determine position information of a PSSCH DMRS based on positioninformation of a PUSCH DMRS (e.g., a position pattern of the PUSCHDMRS). More specifically, the position information of the PSSCH DMRS maybe determined based on Table 7 or Table 8 related to the positioninformation of the PUSCH DMRS. For example, in a single-symbol DMRSstructure (i.e., when a duration for one DMRS is one symbol), theposition of the PSSCH DMRS may be determined based on Table 7. Forexample, in a double-symbol DMRS structure (i.e., when a duration forone DMRS is two symbols), the position of the PSSCH DMRS may bedetermined based on Table 8. In addition, if resources for the sidelinkin a slot is variable, the PSSCH DMRS structure may be determined basedon the PUSCH mapping type B.

TABLE 7 DM-RS positions l l_(d) in PUSCH mapping type A PUSCH mappingtype B sym- dmrs-AdditionalPosition dmrs-AdditionalPosition bols 0 1 2 30 1 2 3 <4 — — — — l₀ l₀ l₀ l₀ 4 l₀ l₀ l₀ l₀ l₀ l₀ l₀ l₀ 5 l₀ l₀ l₀ l₀l₀ l₀, 4 l₀, 4 l₀, 4 6 l₀ l₀ l₀ l₀ l₀ l₀, 4 l₀, 4 l₀, 4 7 l₀ l₀ l₀ l₀ l₀l₀, 4 l₀, 4 l₀, 4 8 l₀ l₀, 7 l₀, 7 l₀, 7 l₀ l₀, 6 l₀, 3, 6 l₀, 3, 6 9 l₀l₀, 7 l₀, 7 l₀, 7 l₀ l₀, 6 l₀, 3, 6 l₀, 3, 6 10 l₀ l₀, 9 l₀, 6, 9 l₀, 6,9 l₀ l₀, 8 l₀, 4, 8 l₀, 3, 6, 9 11 l₀ l₀, 9 l₀, 6, 9 l₀, 6, 9 l₀ l₀, 8l₀, 4, 8 l₀, 3, 6, 9 12 l₀ l₀, 9 l₀, 6, 9 l₀, 5, 8, 11 l₀ l₀, 10 l₀, 5,10 l₀, 3, 6, 9 13 l₀ l₀, 11 l₀, 7, 11 l₀, 5, 8, 11 l₀ l₀, 10 l₀, 5, 10l₀, 3, 6, 9 14 l₀ l₀, 11 l₀, 7, 11 l₀, 5, 8, 11 l₀ l₀, 10 l₀, 5, 10 l₀,3, 6, 9

TABLE 8 DM-RS position l PUSCH mapping type A PUSCH mapping type Bdmrs-AdditionalPosition dmrs-AdditionalPosition l_(d) in symbols 0 1 2 30 1 2 3 <4 — — — — 4 l₀ l₀ — — 5 l₀ l₀ l₀ l₀ 6 l₀ l₀ l₀ l₀ 7 l₀ l₀ l₀ l₀8 l₀ l₀ l₀ l₀, 5 9 l₀ l₀ l₀ l₀, 5 10 l₀ l₀, 8 l₀ l₀, 7 11 l₀ l₀, 8 l₀l₀, 7 12 l₀ l₀, 8 l₀ l₀, 9 13 l₀ l₀, 10 l₀ l₀, 9 14 l₀ l₀, 10 l₀ l₀, 9

In order to determine the position information of the PSSCH DMRS basedon the information of the PUSCH DMRS of Table 7 or Table 8 (e.g., theposition pattern of the PUSCH DMRS), it is necessary to define or(pre-)configure a reference point for defining or interpreting l_(d) andl₀. When the position information of the PSSCH DMRS is N, an actualPSSCH DMRS position may be determined as a position after N symbols fromthe reference point. For example, the l_(d) may indicate a length of asymbol duration as a reference (hereinafter, referred to as a length ofa reference symbol duration). For example, the l₀ may indicate thesymbol position of the first PSSCH DMRS. For example, thedmrs-AdditionalPosition may indicate the number of PSSCH DMRSs. However,the l_(d) and the l₀ of Table 7 or Table 8 may be separately defined forthe PSSCH DMRS.

FIG. 18 shows an example in which a DMRS is mapped to PUSCH resourcesaccording to an embodiment of the present disclosure. The embodiment ofFIG. 18 may be combined with various embodiments of the presentdisclosure.

For example, referring to Table 7, in parameters for a position patternof the PUSCH DMRS, the PUSCH mapping type may be A, thedmrs-AdditionalPosition may be 3, la may be 12, and 10 may be 2. In thiscase, the DMRS may be mapped to symbol indexes 2, 5, 8, and 11, and thepattern in which the DMRS is mapped to the PUSCH resources may be in aform of FIG. 18. Similarly, for example, a position pattern of a PSSCHDMRS may be determined based on the parameters (e.g., l_(d), l₀) for theposition pattern of the PUSCH DMRS and the PUSCH mapping type of Tables7 and 8, and a DMRS may be mapped and transmitted on PSSCH resourcesbased on the position pattern of the PSSCH DMRS. for example, a positionpattern of a PSSCH DMRS may be determined based on parameters (e.g.,l_(d), l₀) for a position pattern of a PSCCH DMRS and a PSSCH mappingtype, defined separately from the parameters for the position pattern ofthe PUSCH DMRS and the PUSCH mapping type of Tables 7 and 8 above, and aDMRS may be mapped and transmitted on PSSCH resources based on theposition pattern of the PSSCH DMRS. for example, a position pattern of aPSSCH DMRS may be determined based on parameters (e.g., l_(d), l₀) for aposition pattern of a PSSCH DMRS and a PSSCH mapping type, definedseparately from the parameters for the position pattern of the PUSCHDMRS and the PUSCH mapping type of Tables 7 and 8 above, and a DMRS maybe mapped and transmitted on PSSCH resources based on the positionpattern of the PSSCH DMRS.

Referring to FIG. 17, in step S1720, the transmitting UE may determineand/or allocate resources for a PSSCH based on the resources for thePSCCH. And, in step S1730, the transmitting UE may determine and/orallocate resources for mapping a PSSCH DMRS based on the resources forthe PSSCH.

More specifically, in consideration of the form in which the PSCCH shownin FIG. 13 is superimposed on the PSSCH, the transmitting UE maydetermine position information of the PSSCH DMRS. To this end, thetransmitting UE may divide resources related to the PSSCH into tworesource block (RB) groups or sub-channel groups in a frequencydimension.

FIG. 19 shows an example in which resources related to a PSSCH aredivided into two RB groups or sub-channel groups according to anembodiment of the present disclosure. The embodiment of FIG. 19 may becombined with various embodiments of the present disclosure.

Referring to FIG. 19, a first RB group represents a set of RBs in anarea in which the PSCCH and the PSSCH are time division multiplexed(TDM) with each other. In addition, a second RB group represents a setof RBs in an area to which only the PSSCH is mapped without the PSCCH.In the present specification, for convenience of description, a set ofRBs in an area in which the PSCCH and the PSSCH are time divisionmultiplexed to each other may be referred to as a first RB group, and aset of sub-channels in an area in which PSCCH and PSSCH are timedivision multiplexed to each other may be referred to as a firstsub-channel group. Meanwhile, a set of RBs in an area to which only thePSSCH is mapped without the PSCCH may be referred to as a second RBgroup, and a set of sub-channels in an area to which only the PSSCH ismapped without the PSCCH may be referred to as a second sub-channelgroup. Hereinafter, a method for the transmitting UE to dividePSSCH-related resources into a first RB group and a second RB group or afirst sub-channel group and a second sub-channel group to determineposition information of the PSSCH DMRS will be described.

For example, in the first RB group or the first sub-channel group, areference point may be (pre-) configured to a symbol immediatelyfollowing a last symbol to which the PSCCH is mapped. In addition, areference point may be (pre-) configured to a symbol after a specificoffset (e.g., the offset is 1) from a last symbol to which the PSCCH ismapped. Accordingly, it is possible to prevent the PSSCH DMRS fromoverlapping the PSCCH resources. In this case, a symbol position of thefirst PSSCH DMRS may be (pre-) configured to 0. Accordingly, the PSSCHDMRS may be directly mapped and transmitted after resources related toPSCCH transmission. In addition, a length of a reference symbol durationmay be a length of an interval from the reference point to a last symbolof the allocated PSSCH resources. That is, the length of the referencesymbol duration may be less than or equal to the length of the actuallyallocated PSSCH resources.

For example, in the first RB group or the first sub-channel group, areference point may be (pre-) configured to a first symbol of sidelinkresources in a slot or a first symbol of the allocated PSSCH resources.In this case, a symbol position of the first PSSCH DMRS may be (pre-)configured to a symbol immediately following a last symbol of PSCCHresources. Accordingly, the PSSCH DMRS may be transmitted immediatelyafter resources related to PSCCH transmission. In addition, a length ofa reference symbol duration may be a length of an interval from thereference point to a last symbol of the allocated PSSCH resources.Herein, a DMRS mapping to a symbol position preceding the symbolposition of the first PSSCH DMRS may be omitted. For example, when aposition pattern of a PSSCH DMRS is (pre-) configured to 4 with thesymbol position of the first PSSCH DMRS, if the symbol position of thefirst PSSCH DMRS is greater than 4, the transmitting UE may map a PSSCHDMRS only to the symbol position of the first PSSCH DMRS.

For example, parameters related to a PSSCH DMRS mapping in the second RBgroup or the second sub-channel group (e.g., a reference point, a symbolposition of a first PSSCH DMRS, a length of a reference symbol duration)may be defined or (pre-) configured to be the same as parameters relatedto the PSSCH DMRS mapping in the above-described the first RB group orthe first sub-channel group. In addition, when the transmitting UE mapsthe PSSCH DMRS in the second RB group or the second sub-channel group, aposition of the PSSCH DMRS may be fixed regardless of a position of a RBor a sub-channel.

FIG. 20 shows a case in which a transient period exists between a symbolduration in an area in which a PSCCH and a PSSCH are frequency divisionmultiplexed to each other and a symbol duration in an area in which onlya PSSCH is transmitted according to an embodiment of the presentdisclosure. The embodiment of FIG. 20 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 20, a transient period may exist between a symbolduration of an area in which a PSCCH and a PSSCH are frequency divisionmultiplexed (hereinafter, FDMed) to each other (e.g., a first period)and a symbol duration of an area in which only a PSSCH is transmitted(e.g., a second period). For example, between a symbol duration of anarea in which a PSCCH and a PSSCH are FDMed to each other (e.g., a firstperiod) and a symbol duration of an area in which only a PSSCH istransmitted (e.g., a second period), when the AGC for the receiving UEis required, a phase continuity may not be guaranteed between the symbolduration of the area in which the PSCCH and the PSSCH are FDMed to eachother in a time domain and the symbol duration of the area in which onlythe PSSCH is transmitted without the PSCCH.

In addition, it may be difficult for the receiving UE to estimatechannel information of another symbol duration by using the PSSCH DMRSof a specific symbol duration. For example, it may be difficult for thereceiving UE to estimate channel information before a transient periodby using the PSSCH DMRS of a symbol duration after the transient period.That is, when a transient period occurs, since characteristics of a RFcircuit may be different, a phase may be randomly changed even if thechannel environment is not changed before and after the transientperiod. For this reason, the receiving UE may not be able to accuratelyestimate the channel before a transient period even if the channelestimation is performed using the PSSCH DMRS transmitted after thetransient period.

Accordingly, it may be required for the transmitting UE to map s PSSCHDMRS even in a symbol duration in which the PSCCH and the PSSCH areFDMed to each other (e.g., the FDM area of FIG. 15). In this case, inthe second RB group or the second sub-channel group, a reference pointmay be (pre-)configured to a first symbol of sidelink resources in aslot or a first symbol of allocated PSSCH resources. In this case, asymbol position of the first PSSCH DMRS may be configured to 0, and alength of a reference symbol duration may be a length of a symbolduration from the reference point to a last symbol of the allocatedPSSCH resources. In order to avoid a situation in which the PSSCH DMRSis mapped in a symbol (duration) in which the receiving UE performs AGC,in the second RB group or the second sub-channel group, for example, areference point may be (pre-)configured to a second symbol of sidelinkresources in a slot or a next symbol of a last symbol of a symbolduration that can potentially be used for performing AGC of thereceiving UE. In this case, for example, a symbol position of the firstPSSCH DMRS may be configured to 0. A length of a reference symbolduration may be a length of a symbol duration from the reference pointto a last symbol of the allocated PSSCH resources.

For example, in the second RB group or the second sub-channel group, areference point may be (pre-)configured to a first symbol of sidelinkresources in a slot or a first symbol of allocated PSSCH resources. Inthis case, a symbol position of the first PSSCH DMRS may be(pre-)configured to 1 or a next symbol of a last symbol of a symbolduration that can potentially be used for AGC performance of thereceiving UE. A length of a reference symbol duration may be a length ofa symbol duration from the reference point to a last symbol of theallocated PSSCH resources.

To configure or determine a position of the PSSCH DMRS, according toreference parameters (for example, a reference point, a symbol positionof a first PSSCH DMRS, a length of a reference symbol duration)respectively configured for the first RB group or the first sub-channelgroup, the transmitting UE may configure and apply a position pattern ofthe PSSCH DMRS, and may map and transmit the PSSCH DMRS. And, accordingto reference parameters (for example, a reference point, a symbolposition of a first PSSCH DMRS, a length of a reference symbol duration)respectively configured for the second RB group or the secondsub-channel group, the transmitting UE may configure and apply a DMRSpattern, and may map and transmit the PSSCH DMRS.

For example, to configure or determine a position of the PSSCH DMRS,according to the same reference parameters (for example, a referencepoint, a symbol position of a first PSSCH DMRS, a length of a referencesymbol duration) for the first RB group and the second RB group, thetransmitting UE may (pre-)configure a position pattern of the PSSCHDMRS. Thereafter, for example, the transmitting UE may map and transmitthe PSSCH DMRS by applying a different position pattern of the PSSCHDMRS according to each RB group. For example, to configure or determinea position of the PSSCH DMRS, according to the same reference parameters(for example, a reference point, a symbol position of a first PSSCHDMRS, a length of a reference symbol duration) for the first sub-channelgroup and the second sub-channel group, the transmitting UE may(pre-)configure a position pattern of the PSSCH DMRS. Thereafter, forexample, the transmitting UE may map and transmit the PSSCH DMRS byapplying a different position pattern of the PSSCH DMRS to eachsub-channel group. Herein, for example, a reference point may be(pre-)configured to a first symbol of sidelink resources in a slot or afirst symbol of allocated PSSCH resources. For example, a referencepoint may be (pre-)configured to a second symbol of sidelink resourcesin a slot or a next symbol of a last symbol of a symbol duration thatcan potentially be used for AGC of the receiving UE. In this case, forexample, a symbol position of the first PSSCH DMRS may be(pre-)configured to 0. For example, a length of a reference symbolduration may be a length of a symbol duration from the PSSCH resourceallocated from the reference point to a last symbol. For example, whenthe transmitting UE applies the position pattern of the PSSCH DMRS tothe first RB group or the first sub-channel group, the transmitting UEmay map the PSSCH DMRS so as not to overlap the PSCCH resources byapplying the position pattern of the PSSCH DMRS based on the referenceparameters configured for the first RB group or the first sub-channelgroup. In addition, when the transmitting UE applies the positionpattern of the PSSSCH DMRS to the second RB or the second sub-channelgroup, the transmitting UE may map and transmit the PSSCH DMRS to thePSSCH resources by applying the position pattern of the PSSCH DMRS basedon the reference parameters configured for the second RB group or thesecond sub-channel group.

Meanwhile, a position pattern of a PSSCH DMRS may be changed flexibly,and information related to the position pattern of the PSSCH DMRS may beindicated by a SCI indicating a PSSCH resource allocation. For example,the transmitting UE may transmit the information related to the positionpattern of the PSSCH DMRS to the receiving UE through the SCI. Forexample, the transmitting UE may inform or indicate a maximum number ofnon-contiguous symbols or symbol groups to which the PSSCH DMRS ismapped, to the receiving UE through a SCI. That is, the transmitting UEmay transmit information related to a maximum number of non-contiguoussymbols or symbol groups to which the PSSCH DMRS is mapped, to thereceiving UE through a SCI. For example, referring to Tables 7 and 8,the transmitting UE may inform or indicate the receiving UE of all orpart of values (e.g., 0, 1, 2, 3) of a dmrs-AdditionalPosition definedfor a PSSCH DMRS through a SCI. For example, candidate values related tothe position pattern of the PSSCH DMRS that the transmitting UE caninform to the receiving UE through a SCI may be (pre-)configured for thetransmitting UE, and the transmitting UE may inform or indicate thereceiving UE of at least one candidate value among the candidate valuesthrough a SCI. For example, candidate values related to the positionpattern of the PSSCH DMRS may be values related to admrs-AdditionalPosition. For example, the receiving UE may determine aposition of a time-frequency resource to which the PSSCH DMRS is mappedbased on the information related to the position pattern of the PSSCHDMRS received through the SCI and the length of the reference symbolduration. And, the receiving UE may receive the PSSCH DMRS from thetransmitting UE at the determined time-frequency resource position. Forexample, information for PSSCH mapping type A or PSSCH mapping type Bmay be (pre-) configured for the transmitting UE, and combinationcandidates combining the information related to the position pattern ofthe PSSCH DMRS and each PSSCH mapping type may be (pre-)configured forthe transmitting UE, the transmitting UE may inform or indicate thereceiving UE of at least one combination candidate among the combinationcandidates through the SCI. That is, the transmitting UE may transmitinformation (or a value) related to at least one combination candidateamong the combination candidates to the receiving UE through the SCI.For example, a value related to the combination candidate combining theinformation related to the position pattern of the PSSCH DMRS and eachmapping type may be {00} when the combination candidate isdmrs-AdditionalPosition=0 and PSSCH mapping type A. For example, a valuemay be {01} when the combination candidate is dmrs-AdditionalPosition=2and PSSCH mapping type A. For example, the value may be {10} when thecombination candidate is dmrs-AdditionalPosition=2 and PSSCH mappingtype B. For example, the value may be {11} when the combinationcandidate is dmrs-AdditionalPosition=3 and PSSCH mapping type B.

For example, a value related to a dmrs-AdditionalPosition may be(pre-)configured for the transmitting UE, and the transmitting UE mayinform or indicate a length of a reference symbol duration to thereceiving UE through a SCI. That is, the transmitting UE may transmitinformation related to the length of the reference symbol duration tothe receiving UE through the SCI. For example, some candidate valuesrelated to the length of the reference symbol duration in considerationof an overhead of a SCI may be (pre-) configured for the transmittingUE, and the transmitting UE may inform or indicate the receiving UE ofat least one candidate value among the candidate values through the SCI.For example, information for PSSCH mapping type A or PSSCH mapping typeB may be (pre-) configured for the transmitting UE, and combinationcandidates combining the length of the reference symbol duration andeach PSSCH mapping type may be (pre-)configured for the transmitting UE,and the transmitting UE may inform or indicate the receiving UE of atleast one combination candidate among the combination candidates throughthe SCI. That is, the transmitting UE may transmit information (or avalue) related to at least one combination candidate among thecombination candidates to the receiving UE through the SCI.Alternatively, for example, when the length of the reference symbolduration is a length of the actually allocated PSSCH resources, thelength of the reference symbol duration may be pre-configured for theUE.

For example, combination candidates combining thedmrs-AdditionalPosition and the length of the reference symbol durationare (pre-)configured for the transmitting UE, and the transmitting UEmay inform or indicate the receiving UE of at least one combinationcandidate among the combination candidates through the SCI. That is, thetransmitting UE may transmit information (or a value) related to atleast one combination candidate among the combination candidates to thereceiving UE through the SCI. For example, a value of the combinationcandidate combining the dmrs-AdditionalPosition and the length of thereference symbol duration may be {00} when the combination candidate isthe dmrs-AdditionalPosition=0 and the l_(d)=5. For example, the valuemay be {01} when the combination candidate is thedmrs-AdditionalPosition=0 and the l_(d)=8. For example, the value may be{10} when the combination candidate is the dmrs-AdditionalPosition=3 andthe l_(d)=8. For example, the value may be {11} when the combinationcandidate is the dmrs-AdditionalPosition=3 and the l_(d)=13.

For example, information for PSSCH mapping type A or PSSCH mapping typeB may be (pre-) configured for the transmitting UE, and combinationcandidates combining the dmrs-AdditionalPosition, the length of thereference symbol interval, and each PSSCH mapping type may be(pre-)configured for the transmitting UE, and the transmitting UE mayinform or indicate the receiving UE of at least one combinationcandidate among the combination candidates through the SCI. That is, thetransmitting UE may transmit information (or a value) related to atleast one combination candidate among the combination candidates to thereceiving UE through the SCI.

Meanwhile, a single SCI may indicate allocation of a plurality of PSSCHresources. For example, the transmitting UE may indicate a plurality ofPSSCH resources to the receiving UE through a single SCI. That is, thetransmitting UE may transmit information related to allocation of aplurality of PSSCH resource to the receiving UE through a single SCI.For example, the transmitting UE may allocate initial transmissionresources and future retransmission resources. That is, the futureretransmission resources may be resources that follows the initialtransmission resources in the time domain. Alternatively, for example,the transmitting UE may allocate a plurality of initial transmissionresources in advance. In this case, information related to the positionpattern of the PSSCH DMRS may be separately indicated for each PSSCHresource. For example, the transmitting UE may separately transmit orindicate the information related to the position pattern of the PSSCHDMRS for each PSSCH resource to the receiving UE through a SCI. Forexample, when information related to allocation of N PSSCH resources isindicated by a single SCI, information related to position patterns of NPSSCH DMRSs may be indicated together. For example, when thetransmitting UE transmits or indicates the receiving UE informationrelated to the allocation of N PSSCH resources through a SCI, thetransmitting UE may transmit or indicate the receiving UE together withinformation related to the position patterns of the N PSSCH DMRSsthrough the SCI. For example, based on information related to theposition pattern of the PSSCH DMRS for each PSSCH resource and/or thelength of the reference symbol duration at a time when each PSSCH istransmitted, the transmitting UE may determine a position of atime-frequency resource to which the PSSCH DMRS is mapped. And, forexample, based on information related to the position pattern of thePSSCH DMRS for each PSSCH resource and/or the length of the referencesymbol duration at a time when each PSSCH is transmitted, the receivingUE may determine a position of a time-frequency resource to which thePSSCH DMRS is mapped. However, in the case of the above method, the SCIoverhead may become excessive.

For example, when the transmitting UE transmits information related to aposition pattern of one PSSCH DMRS for a plurality of PSSCH resourcesthrough a SCI, the position pattern of the actually transmitted PSSCHDMRS at a time each PSSCH is transmitted may be different based on alength of a reference symbol duration at the time the PSSCH istransmitted. For example, the transmitting UE may transmit or indicateinformation related to the position pattern of one PSSCH DMRS for theplurality of PSSCH resources to the receiving UE through a single SCI,and the receiving UE may determine the position of a PSSCH DMRS mappingresource for the plurality of PSSCH resources indicated by the singleSCI based on the information related to the position pattern of the onePSSCH DMRS. For example, based on information related to a positionpattern of one PSSCH DMRS for a plurality of PSSCH resources and/or alength of a reference symbol duration at a time when the PSSCH istransmitted, the transmitting UE may determine a position of atime-frequency resource to which the PSSCH DMRS is mapped. For example,based on information related to a position pattern of one PSSCH DMRS fora plurality of PSSCH resources and/or a length of a reference symbolduration at a time when the PSSCH is transmitted, the receiving UE maydetermine a position of a time-frequency resource to which the PSSCHDMRS is mapped. That is, even when the information related to theposition pattern of the PSSCH DMRS is the same for the plurality ofPSSCH resources, a location of a time-frequency resource to which anactual PSSCH DMRS is mapped may be different based on a length of areference symbol duration at a time point at which each PSSCH istransmitted.

For example, combination candidates combining information related to theposition pattern of the PSSCH DMRS for each of the plurality of PSSCHresources may be (pre-)configured for the transmitting UE, and thetransmitting UE may inform or indicate the receiving UE of at least onecombination candidate among the combination candidates through the SCI.That is, the transmitting UE may transmit information (or a value)related to at least one combination candidate among the combinationcandidates to the receiving UE through the SCI. For example, a value ofthe combination candidate combining information related to the positionpattern of the PSSCH DMRS for each of the plurality of PSSCH resourcesmay be {00} when the combination candidate is dmrs-AdditionalPosition=0of a first PSSCH and the dmrs-AdditionalPosition=0 of a second PSSCH.For example, the value may be {01} when the combination candidate isdmrs-AdditionalPosition=3 of a first PSSCH and dmrs-AdditionalPosition=0of a second PSSCH. For example, the value may be {10} when thecombination candidate is dmrs-AdditionalPosition=0 of a first PSSCH anddmrs-AdditionalPosition=3 of a second PSSCH. For example, the value maybe {11} when the combination candidate is dmrs-AdditionalPosition=3 of afirst PSSCH and dmrs-AdditionalPosition=3 of a second PSSCH.

For example, based on information related to the position pattern of thePSSCH DMRS for each PSSCH resource and/or the length of the referencesymbol duration at the time when the PSSCH is transmitted, thetransmitting UE may determine a position of a time-frequency resource towhich the PSSCH DMRS is mapped. For example, the transmitting UE may mapthe PSSCH DMRS on the determined time-frequency resource and transmitthe PSSCH DMRS to the receiving UE. For example, based on informationrelated to the position pattern of the PSSCH DMRS for each PSSCHresource and/or the length of the reference symbol duration at the timewhen the PSSCH is transmitted, the receiving UE may determine a positionof a time-frequency resource to which the PSSCH DMRS is mapped. Forexample, the receiving UE may receive the PSSCH DMRS from thetransmitting UE on the determined time-frequency resource.

Meanwhile, referring to Tables 7 and 8, for example, according to avalue of dmrs-AdditionalPosition defined for a PSSCH DMRS or a densityof a PSSCH DMRS, a definition or a corresponding value of a referencepoint, a symbol position 10 of a first PSSCH DMRS, and/or a length l_(d)of a reference symbol duration may be different. For example, when avalue of dmrs-AdditionalPosition is less than or equal to a specificthreshold (for example, if a value of dmrs-AdditionalPosition is 1 or2), a value of l₀ may be configured or defined so that a first PSSCHDMRS is mapped after a resource related to PSCCH transmission in a timedomain. For example, when a value of dmrs-AdditionalPosition is lessthan or equal to a specific threshold, the transmitting UE may map thePSSCH DMRS based on a value of l₀ configured or defined so that a firstPSSCH DMRS is mapped immediately after a resource related to PSCCHtransmission, and may transmit the PSSCH DMRS to the receiving UE.Specifically, for example, if an ending symbol index of a PSCCH resourceis 3, l₀ may be 4 (e.g., when a reference point is a first symbol of aPSSCH resource) or 3 (e.g., when a reference point is a second symbol ofa PSSCH resource). On the other hand, if a value ofdmrs-AdditionalPosition exceeds a specific threshold, a value of l₀ maybe defined or configured so that a first PSSCH DMRS is mapped after anAGC symbol or an AGC period in a time domain. For example, if a value ofdmrs-AdditionalPosition exceeds a specific threshold, the transmittingUE may map a PSSCH DMRS based on a value of 10 configured or defined sothat a first PSSCH DMRS is mapped immediately following an AGC symbol oran AGC period in a time domain, and may transmit the PSSCH DMRS to thereceiving UE. Specifically, for example, when an AGC symbol is a firstsymbol of a PSSCH resource, a value of l₀ may be 1 (e.g., when areference point is a first symbol of a PSSCH resource) or 0 (e.g., whena reference point is a second symbol of a PSSCH resource).

Meanwhile, for example, based on the number of sub-channels, the numberof RBs constituting a PSCCH (i.e., the number of RBs included in a PSCCHresource, hereinafter the number of RBs in the PSCCH) and/or the numberof sub-channels allocated for the PSSCH, a reference point, a symbolposition (l₀) of a first PSSCH DMRS, and/or a length (l_(d)) of areference symbol duration may be defined differently. For example, basedon the number of sub-channels, the number of RBs in the PSCCH and/or thenumber of sub-channels allocated for the PSSCH, a symbol position (l₀)of a first PSSCH DMRS, and/or a length (l_(d)) of a reference symbolduration may be different. For example, when the number of RBs in thePSCCH is equal to a sub-channel size or when the number of RBs in thePSCCH is greater than or equal to a specific threshold, a value of l₀may be configured or defined so that a first PSSCH DMRS is mapped aftera resource related to the PSCCH transmission in a time domain. In thiscase, for example, a case in which the number of RBs in the PSCCH isequal to the sub-channel size or a case in which the number of RBs inthe PSCCH is equal to or greater than a specific threshold value mayinclude a case in which no RB remains after mapping the PSCCH in thesub-channel (that is, the number of remaining RBs is 0) or a case inwhich the number of RBs remaining after mapping the PSCCH in thesub-channel is K (e.g., the value of K is 1 or 2) RBs or less. And/or,for example, when the number of sub-channels allocated for the PSSCH isone, a value of l₀ may be configured or defined so that a first PSSCHDMRS is mapped after a resource related to PSCCH transmission in a timedomain And/or, for example, when all of symbol positions of the PSSCHDMRS exist within a symbol duration of the PSCCH, a value of l₀ may beconfigured or defined so that to first PSSCH DMRS is mapped after aresource related to PSCCH transmission in a time domain. For example,based on a value of l₀ configured or defined so that a first PSSCH DMRSis mapped immediately following a resource related to PSCCHtransmission, the transmitting UE may map the PSSCH DMRS and transmitthe PSSCH DMRS to the receiving UE. Specifically, for example, if anending symbol index of a PSCCH resource is 3, the l₀ may be 4 (e.g.,when a reference point is a first symbol of the PSSCH resource) or 3(e.g., when a reference point is a second symbol of the PSSCH resource).

Referring to FIG. 17, in step S1740, the transmitting UE may transmitthe PSSCH DMRS to the receiving UE. The transmission may includeunicast, broadcast or groupcast. For example, the transmitting UE maymap the PSSCH DMRS to the PSSCH resource according to variousembodiments of the present disclosure.

According to an embodiment of the present disclosure, the transmittingUE may efficiently map and/or transmit the PSSCH DMRS on the PSSCHresource. Accordingly, in terms of the receiving UE, a detectionperformance of the PSSCH DMRS may be improved, and the receiving UE mayefficiently decode the PSSCH.

FIG. 21 shows a procedure in which a transmitting UE transmits a DMRS toa receiving UE through a PSSCH according to an embodiment of the presentdisclosure. FIG. 21 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 21, in step S2110, the transmitting UE may transmit aSCI to the receiving UE through a PSCCH. For example, the SCI mayinclude information related to a pattern of a DMRS. For example, theinformation related to the pattern of the DMRS may include informationfor the number of DMRSs.

In step S2120, the transmitting UE may map the DMRS on resources relatedto a PSSCH. For example, the transmitting UE may map the DMRS on theresources related to the PSSCH based on the information related to thepattern of the DMRS and a length of a symbol duration of the PSSCHrelated to the PSCCH. For example, the length of the symbol duration ofthe PSSCH may be pre-configured for the UE. For example, the length ofthe symbol duration of the PSSCH related to the PSCCH may include alength of a reference symbol duration described above. For example, thelength of the reference symbol duration may be a length of the actuallyallocated PSSCH resources. For example, a pattern of DMRS mapped on theresources related to the PSSCH may be different according to the lengthof the symbol duration of the PSSCH and the number of DMRSs.

According to an embodiment of the present disclosure, the transmittingUE may map a first DMRS from a second symbol in a slot related to thePSSCH based on the number of DMRSs exceeding a pre-configured threshold.That is, for example, the transmitting UE may map a first DMRS after anAGC symbol in a slot related to the PSSCH based on the number of DMRSsexceeding a pre-configured threshold. For example, the transmitting UEmay map a first DMRS to a next symbol of an AGC symbol in a slot relatedto the PSSCH based on the number of DMRSs exceeding a pre-configuredthreshold.

According to an embodiment of the present disclosure, the transmittingUE may map a first DMRS to symbols after a last symbol of the PSCCHbased on the number of DMRSs being less than or equal to apre-configured threshold. For example, the transmitting UE may map afirst DMRS to a next symbol of a last symbol of the PSCCH based on thenumber of DMRSs being less than or equal to a pre-configured threshold.For example, the transmitting UE may map a first DMRS to symbols after apre-configured offset value from a last symbol of the PSCCH based on thenumber of DMRSs being less than or equal to a pre-configured threshold.For example, the transmitting UE may map a first DMRS to a next symbolof a last symbol of the PSCCH based on the number of DMRSs being lessthan or equal to a pre-configured threshold. For example, thepre-configured offset value may be 1.

TABLE 9 DM-RS positions l PSSCH mapping type A PSSCH mapping type Bl_(d) in dmrs-Additional Position dmrs-AdditionalPosition symbols 0 1 23 0 1 2 3 6 l₀ l₀ l₀ l₀ l₀ l₀, 5 l₀, 5 l₀, 5 7 l₀ l₀ l₀ l₀ l₀ l₀, 5 l₀,5 l₀, 5 8 l₀ l₀ l₀ l₀ l₀ l₀, 5 l₀, 5 l₀, 5 9 l₀ l₀, 8 l₀, 8 l₀, 7 l₀ l₀,7 l₀, 4, 7 l₀, 4, 7 10 l₀ l₀, 8 l₀, 8 l₀, 7 l₀ l₀, 7 l₀, 4, 7 l₀, 4, 711 l₀ l₀, 10 l₀, 7, 10 l₀, 7, 10 l₀ l₀, 9 l₀, 5, 9 l₀, 4, 7, 10 12 l₀l₀, 10 l₀, 7, 10 l₀, 7, 10 l₀ l₀, 9 l₀, 5, 9 l₀, 4, 7, 10 13 l₀ l₀, 10l₀, 7, 10 l₀, 6, 9, 12 l₀ l₀, 11 l₀, 6, 11 l₀, 4, 7, 10

More specifically, Table 9 above may indicate a pattern of a DMRS mappedon resources related to a PSSCH based on a length of a symbol durationof the PSSCH, the PSSCH mapping type, and dmrs-AdditionalPosition (e.g.,the number of DMRSs). For example, the l_(d) value may be a length of asymbol duration of the actually allocated PSSCH including an AGC symbol.For example, the value l₀ may be a symbol index in a slot related to thePSSCH to which a first DMRS is mapped. For example, Table 9 may be atable showing a position of a DMRS mapped on resources related to aPSSCH by symbol index values in a slot related to the PSSCH including anAGC symbol based on a length of the symbol duration of the PSSCH, thePSSCH mapping type, and dmrs-AdditionalPosition (e.g., the number ofDMRSs). For example, a symbol mapped to symbol index 0 in Table 9 may bean AGC symbol.

For example, referring to Table 9, when a value ofdmrs-AdditionalPosition is less than or equal to a pre-configuredthreshold value (e.g., 1), the transmitting UE may map a first PSSCHDMRS to resources after resources related to PSCCH transmission in atime domain. For example, when a value of dmrs-AdditionalPosition is 1and the PSSCH mapping type is A, the transmitting UE may determine avalue l₀ based on a length of a symbol duration of the PSCCH. Forexample, when the length of the symbol duration of the PSCCH is 2, thetransmitting UE may determine a value l₀ to be 3 so that a first DMRS islocated after an AGC symbol included in the symbol duration of thePSSCH. For example, when a value of dmrs-AdditionalPosition is 1, alength of a symbol duration of the PSSCH is 9, and the PSSCH mappingtype is A, the transmitting UE may map a PSSCH DMRS to symbol index 3and symbol index 8 in a slot related to the PSSCH.

For example, referring to Table 9, when a value ofdmrs-AdditionalPosition exceeds a pre-configured threshold value (e.g.,1), the transmitting UE may map a first PSSCH DMRS to a symbolimmediately following an AGC symbol in a slot related to the PSSCH. Forexample, when a value of dmrs-AdditionalPosition is 2 and a PSSCHmapping type is B, a value of l₀ may be determined to be 1. That is, forexample, the transmitting UE may determine a value l₀ to be 1 so that afirst DMRS is located after an AGC symbol in a slot related to thePSSCH. For example, when a value of dmrs-AdditionalPosition is 2, alength of a symbol duration of the PSSCH is 9, and the PSSCH mappingtype is B, the transmitting UE may map a PSSCH DMRS to symbol index 1,symbol index 4, and symbol index 8 in a slot related to the PSSCH.

TABLE 10 DM-RS position l PSCCH duration 2 symbols PSCCH duration 3symbols l_(d) in Number of PSSCH DM-RS Number of PSSCH DM-RS symbols 2 34 2 3 4 6 1, 5 1, 5 7 1, 5 1, 5 8 1, 5 1, 5 9 3, 8 1, 4, 7 4, 8 1, 4, 710 3, 8 1, 4, 7 4, 8 1, 4, 7 11 3, 10 1, 5, 9 1, 4, 7, 10 4, 10 1, 5, 91, 4, 7, 10 12 3, 10 1, 5, 9 1, 4, 7, 10 4, 10 1, 5, 9 1, 4, 7, 10 13 3,10 1, 6, 11 1, 4, 7, 10 4, 10 1, 6, 11 1, 4, 7, 10

For example, referring to Table 10, the transmitting UE may determine apattern of a DMRS mapped on resources related to a PSSCH based on alength of a symbol duration of a PSCCH, a length of a symbol duration ofthe PSSCH, and the number of DMRSs. For example, the transmitting UE maymap the DMRS on the resource related to the PSSCH based on Table 10above. For example, when a length of a symbol duration of the PSCCH is2, the number of PSSCH DMRSs is 4, and a length of a symbol duration ofthe PSSCH is 11, the positions of the PSSCH DMRSs may be 1, 4, 7, and10. For example, the 1, 4, 7, and 10 may represent values of a symbolindex in a slot related to the PSSCH. That is, for example, when alength of a symbol duration of the PSCCH is 2, the number of PSSCH DMRSsis 4, and a length of a symbol duration of the PSSCH is 11, thetransmitting UE may map the PSSCH DMRS to a second symbol, a fifthsymbol, an eighth symbol, and an eleventh symbol in a slot related tothe PSSCH. For example, when a length of a symbol duration of the PSCCHis 3, the number of PSSCH DMRSs is 2, and a length of a symbol durationof the PSSCH is 11, the positions of the PSSCH DMRS may be 4 or 10. Forexample, the 4 and 10 may represent values of a symbol index in a slotrelated to the PSSCH. That is, for example, when a length of a symbolduration of the PSCCH is 3, the number of PSSCH DMRSs is 2, and a lengthof a symbol duration of the PSSCH is 11, the transmitting UE may map thePSSCH DMRS to a fifth symbol and an eleventh symbol in a slot related tothe PSSCH.

In step S2130, the transmitting UE may transmit the DMRS to thereceiving UE through the PSSCH.

FIG. 22 shows a method in which a first device transmits a PSSCH DMRS toa second device through a PSSCH according to an embodiment of thepresent disclosure. FIG. 22 may be combined with various embodiments ofthe present disclosure.

Referring to FIG. 22, in step S2210, the first device 100 may select asynchronization source based on a sidelink synchronization priority. Forexample, the synchronization source may include at least one of a GNSS,a base station, or a terminal. For example, the sidelink synchronizationpriority may be configured based on Table 5 or Table 6 described above.For example, the sidelink priority may be pre-configured for the firstdevice 100.

In step S2220, the first device 100 may obtain synchronization based onthe synchronization source. For example, the first device 100 mayperform synchronization with the selected a synchronization source.

In step S2230, the first device 100 may transmit asidelink-synchronization signal block (S-SSB) block to the second device200 based on the obtained synchronization. For example, the S-SSB blockmay include a sidelink primary synchronization signal (S-PSS), asidelink secondary synchronization signal (S-SSS), and a physicalsidelink broadcast channel (PSBCH).

In step S2240, the first device 100 may transmit information related toa pattern of a PSSCH DMRS for decoding a PSSCH through a SCI on a PSCCHto the second device 200. For example, the information related to thepattern of the PSSCH DMRS may include information for the number ofPSSCH DMRSs.

In step S2250, the first device 100 may map the PSSCH DMRS to timeresources related to the PSSCH based on the information related to thepattern of the PSSCH DMRS and a duration of time resources scheduled fortransmission of the PSSCH related to the PSCCH. For example, the firstdevice 100 may map a first PSSCH DMRS to a second symbol in a slotrelated to the PSSCH based on the number of PSSCH DMRSs exceeding apre-configured threshold. For example, the first symbol of the PSSCH mayinclude an AGC symbol. For example, frequency division multiplexing(FDM) may be performed on resources related to the PSCCH and theresources related to the PSSCH.

For example, the duration of the time resources scheduled fortransmission of the PSSCH may be a symbol duration of the PSSCH. Forexample, the first device 100 may map the PSSCH DMRS to the secondsymbol, a fifth symbol and an eighth symbol in the slot related to thePSSCH based on the length of the symbol duration of the PSSCH being 9and the number of PSSCH DMRSs being 3. For example, the first device 100may map the PSSCH DMRS to the second symbol, a sixth symbol, and a tenthsymbol in the slot related to the PSSCH based on the length of thesymbol duration of the PSSCH being 11 and the number of PSSCH DMRSsbeing 3. For example, the first device 100 may map the PSSCH DMRS to thesecond symbol, a seventh symbol, and a twelfth symbol in the slotrelated to the PSSCH based on the length of the symbol duration of thePSSCH being 13 and the number of PSSCH DMRSs being 3. For example, thefirst device 100 may map the PSSCH DMRS to the second symbol, a fifthsymbol, an eighth and a eleventh symbol in the slot related to the PSSCHbased on the length of the symbol duration of the PSSCH being 13 and thenumber of PSSCH DMRSs being 4.

For example, the first device 100 may map a first PSSCH DMRS to symbolsafter a last symbol of the PSCCH based on the number of PSSCH DMRSsbeing less than or equal to a pre-configured threshold. For example, thefirst device 100 may map a first PSSCH DMRS to a next symbol of the lastsymbol of the PSCCH based on the number of PSSCH DMRSs being less thanor equal to a pre-configured threshold. For example, the first device100 may map a first PSSCH DMRS to symbols after a pre-configured offsetvalue from a last symbol of the PSCCH based on the number of PSSCH DMRSsbeing less than or equal to a pre-configured threshold. For example, thepre-configured offset value may be 1. For example, time divisionmultiplexing (TDM) is performed on resources related to the PSCCH andthe resources related to the PSSCH. For example, the first device 100may map the PSSCH DMRS to a fourth symbol and a ninth in the slotrelated to the PSSCH based on the length of the symbol duration of thePSSCH being 9 and the number of PSSCH DMRSs being 2. For example, thefirst device 100 may map the PSSCH DMRS to the second symbol and a sixthsymbol in the slot related to the PSSCH based on the length of thesymbol duration of the PSSCH being 6 and the number of PSSCH DMRSs being2.

In step S2260, the first device 100 may transmit the PSSCH DMRS to thesecond device 200 through the PSSCH. For example, the first device 100may transmit the PSSCH DMRS mapped onto resources related to the PSSCHto the second device 200 through the PSSCH.

The above-described embodiment may be applied to various devices to bedescribed below. First, for example, the processor 102 of the firstdevice 100 may select a synchronization source based on a sidelinksynchronization priority. And, for example, the processor 102 of thefirst device 100 may obtain synchronization based on the synchronizationsource. And, for example, the processor 102 of the first device 100 maycontrol the transceiver 106 to transmit a sidelink-synchronizationsignal block (S-SSB) block to a second device 200 based on the obtainedsynchronization. And, for example, the processor 102 of the first device100 may control the transceiver 106 to transmit information related to apattern of a PSSCH DMRS for decoding a PSSCH through a SCI on a PSCCH tothe second device 200. And, for example, the processor 102 of the firstdevice 100 may map the PSSCH DMRS to time resources related to the PSSCHbased on the information related to the pattern of the PSSCH DMRS and aduration of time resources scheduled for transmission of the PSSCHrelated to the PSCCH. And, for example, the processor 102 of the firstdevice 100 may control the transceiver 106 to transmit the PSSCH DMRS tothe second device 200 through the PSSCH.

According to an embodiment of the present disclosure, a first deviceconfigured to perform wireless communication may be provided. Forexample, the first device may comprise: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers.For example, the one or more processors may execute the instructions to:select a synchronization source based on a sidelink synchronizationpriority, obtain synchronization based on the synchronization source,transmit a sidelink-synchronization signal block (S-SSB) block to asecond device based on the obtained synchronization, transmitinformation related to a pattern of a PSSCH DMRS for decoding a PSSCHthrough a SCI on a PSCCH to the second device, map the PSSCH DMRS totime resources related to the PSSCH based on the information related tothe pattern of the PSSCH DMRS and a duration of time resources scheduledfor transmission of the PSSCH related to the PSCCH, and transmit thePSSCH DMRS to the second device through the PSSCH. For example, theS-SSB block may include a sidelink primary synchronization signal(S-PSS), a sidelink secondary synchronization signal (S-SSS), and aphysical sidelink broadcast channel (PSBCH).

According to an embodiment of the present disclosure, an apparatusconfigured to control a first user equipment (UE) may be provided. Forexample, the apparatus may comprise: one or more processors; and one ormore memories operably connected to the one or more processors andstoring instructions. For example, the one or more processors mayexecute the instructions to: select a synchronization source based on asidelink synchronization priority, obtain synchronization based on thesynchronization source, transmit a sidelink-synchronization signal block(S-SSB) block to a second UE based on the obtained synchronization,transmit information related to a pattern of a PSSCH DMRS for decoding aPSSCH through a SCI on a PSCCH to the second UE, map the PSSCH DMRS totime resources related to the PSSCH based on the information related tothe pattern of the PSSCH DMRS and a duration of time resources scheduledfor transmission of the PSSCH related to the PSCCH, and transmit thePSSCH DMRS to the second UE through the PSSCH. For example, the S-SSBblock may include a sidelink primary synchronization signal (S-PSS), asidelink secondary synchronization signal (S-SSS), and a physicalsidelink broadcast channel (PSBCH).

According to an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, cause a first device to:select a synchronization source based on a sidelink synchronizationpriority, obtain synchronization based on the synchronization source,transmit a sidelink-synchronization signal block (S-SSB) block to asecond device based on the obtained synchronization, transmitinformation related to a pattern of a PSSCH DMRS for decoding a PSSCHthrough a SCI on a PSCCH to the second device, map the PSSCH DMRS totime resources related to the PSSCH based on the information related tothe pattern of the PSSCH DMRS and a duration of time resources scheduledfor transmission of the PSSCH related to the PSCCH, and transmit thePSSCH DMRS to the second device through the PSSCH. For example, theS-SSB block may include a sidelink primary synchronization signal(S-PSS), a sidelink secondary synchronization signal (S-SSS), and aphysical sidelink broadcast channel (PSBCH).

FIG. 23 shows a method for a second device to receive a PSSCH DMRS froma first device according to an embodiment of the present disclosure.FIG. 23 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 23, in step S2310, the second device 200 may receive asidelink-synchronization signal block (S-SSB) block from the firstdevice 100. For example, the S-SSB block may include a sidelink primarysynchronization signal (S-PSS), a sidelink secondary synchronizationsignal (S-SSS), and a physical sidelink broadcast channel (PSBCH). Forexample, the S-SSB block may be transmitted by the first device 100through synchronization obtained based on the synchronization source.For example, the synchronization source may be selected based on asidelink synchronization priority. For example, the synchronizationsource may include at least one of a GNSS, a base station, or aterminal.

In step S2320, the second device 200 may receive information related toa pattern of a PSSCH DMRS for decoding a PSSCH through a SCI on a PSCCHfrom the first device 100. For example, the information related to thepattern of the PSSCH DMRS may include information for the number ofPSSCH DMRSs.

For example, a first PSSCH DMRS may be mapped to a second symbol in aslot related to the PSSCH based on the number of PSSCH DMRSs exceeding apre-configured threshold. For example, the first symbol in the slotrelated to the PSSCH may include an automatic gain control (AGC) symbol.For example, frequency division multiplexing (FDM) may be performed onresources related to the PSCCH and the resources related to the PSSCH.

For example, the duration of the time resources scheduled fortransmission of the PSSCH may be a symbol duration of the PSSCH. Forexample, the PSSCH DMRS may be mapped to the second symbol, a fifthsymbol and an eighth symbol in the slot related to the PSSCH based onthe length of the symbol duration of the PSSCH being 9 and the number ofPSSCH DMRSs being 3. For example, the PSSCH DMRS may be mapped to thesecond symbol, a sixth symbol, and a tenth symbol in the slot related tothe PSSCH based on the length of the symbol duration of the PSSCH being11 and the number of PSSCH DMRSs being 3. For example, the PSSCH DMRSmay be mapped to the second symbol, a seventh symbol, and a twelfthsymbol in the slot related to the PSSCH based on the length of thesymbol duration of the PSSCH being 13 and the number of PSSCH DMRSsbeing 3. For example, the PSSCH DMRS may be mapped to the second symbol,a fifth symbol, an eighth and a eleventh symbol in the slot related tothe PSSCH based on the length of the symbol duration of the PSSCH being13 and the number of PSSCH DMRSs being 4.

For example, a first PSSCH DMRS may be mapped to symbols after a lastsymbol of the PSCCH based on the number of PSSCH DMRSs being less thanor equal to a pre-configured threshold. For example, a first PSSCH DMRSmay be mapped to a next symbol of the last symbol of the PSCCH based onthe number of PSSCH DMRSs being less than or equal to a pre-configuredthreshold. For example, a first PSSCH DMRS may be mapped to symbolsafter a pre-configured offset value from a last symbol of the PSCCHbased on the number of PSSCH DMRSs being less than or equal to apre-configured threshold. For example, the pre-configured offset valuemay be 1. For example, time division multiplexing (TDM) is performed onresources related to the PSCCH and the resources related to the PSSCH.For example, the PSSCH DMRS may be mapped to a fourth symbol and a ninthin the slot related to the PSSCH based on the length of the symbolduration of the PSSCH being 9 and the number of PSSCH DMRSs being 2. Forexample, the PSSCH DMRS may be mapped to the second symbol and a sixthsymbol in the slot related to the PSSCH based on the length of thesymbol duration of the PSSCH being 6 and the number of PSSCH DMRSs being2.

In step S2330, the second device 200 may receive a PSSCH DMRS from thefirst device 100 through a PSSCH based on the information related to thepattern of the PSSCH DMRS and a duration of time resources scheduled fortransmission of the PSSCH related to the PSCCH.

The above-described embodiment may be applied to various devices to bedescribed below. First, for example, the processor 202 of the seconddevice 200 may control the transceiver 206 to receive asidelink-synchronization signal block (S-SSB) block from the firstdevice 100. And, for example, the processor 202 of the second device 200may control the transceiver 206 to receive information related to apattern of a PSSCH DMRS for decoding a PSSCH through a SCI on a PSCCHfrom the first device 100. And, for example, the processor 202 of thesecond device 200 may control the transceiver 206 to receive a PSSCHDMRS from the first device 100 through a PSSCH based on the informationrelated to the pattern of the PSSCH DMRS and a duration of timeresources scheduled for transmission of the PSSCH related to the PSCCH.

According to an embodiment of the present disclosure, a second deviceconfigured to perform wireless communication may be provided. Forexample, the second device may comprise: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers.For example, the one or more processors may execute the instructions to:receive, from the first device, a sidelink-synchronization signal block(S-SSB) block, receive, from the first device through a SCI on a PSCCH,information related to a pattern of a PSSCH DMRS for decoding a PSSCH,and receive a PSSCH DMRS, from the first device through a PSSCH, basedon the information related to the pattern of the PSSCH DMRS and aduration of time resources scheduled for transmission of the PSSCHrelated to the PSCCH.

FIG. 24 shows a method in which a first device transmits a DMRS to asecond device through a PSSCH according to an embodiment of the presentdisclosure. FIG. 24 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 24, in step S2410, the first device 100 may transmit asidelink control information (SCI) including information related to apattern of a demodulation reference signal (DMRS) to the second device200 through a physical sidelink control channel (PSCCH). For example,the DMRS may be a reference signal for decoding a physical sidelinkshared channel (PSSCH). For example, the information related to thepattern of the DMRS may include information for the number of DMRSs.

In step S2420, the first device 100 may map a DMRS onto resourcesrelated to a physical sidelink shared channel (PSSCH) based on theinformation related to the pattern of the DMRS and a length of a symbolduration of the PSSCH related to the PSCCH. For example, the firstdevice 100 may map a first DMRS to a second symbol in a slot related tothe PSSCH based on the number of DMRSs exceeding a pre-configuredthreshold. For example, the first symbol in the slot related to thePSSCH may include an automatic gain control (AGC) symbol. For example,frequency division multiplexing (FDM) may be performed on resourcesrelated to the PSCCH and the resources related to the PSSCH. Forexample, the first device 100 may map the DMRS to the second symbol, afifth symbol and an eighth symbol in the slot related to the PSSCH basedon the length of the symbol duration of the PSSCH being 9 and the numberof DMRSs being 3. For example, the first device 100 may map the DMRS tothe second symbol, a sixth symbol, and a tenth symbol in the slotrelated to the PSSCH based on the length of the symbol duration of thePSSCH being 11 and the number of DMRSs being 3. For example, the firstdevice 100 may map the DMRS to the second symbol, a seventh symbol, anda twelfth symbol in the slot related to the PSSCH based on the length ofthe symbol duration of the PSSCH being 13 and the number of DMRSs being3. For example, the first device 100 may map the DMRS to the secondsymbol, a fifth symbol, an eighth and a eleventh symbol in the slotrelated to the PSSCH based on the length of the symbol duration of thePSSCH being 13 and the number of DMRSs being 4.

For example, the first device 100 may map a first DMRS to symbols aftera last symbol of the PSCCH based on the number of DMRSs being less thanor equal to a pre-configured threshold. For example, the first device100 may map a first DMRS to a next symbol of the last symbol of thePSCCH based on the number of DMRSs being less than or equal to apre-configured threshold. For example, the first device 100 may map afirst DMRS to symbols after a pre-configured offset value from a lastsymbol of the PSCCH based on the number of DMRSs being less than orequal to a pre-configured threshold. For example, the pre-configuredoffset value may be 1. For example, time division multiplexing (TDM) isperformed on resources related to the PSCCH and the resources related tothe PSSCH. For example, the first device 100 may map the DMRS to afourth symbol and a ninth in the slot related to the PSSCH based on thelength of the symbol duration of the PSSCH being 9 and the number ofDMRSs being 2. For example, the first device 100 may map the DMRS to thesecond symbol and a sixth symbol in the slot related to the PSSCH basedon the length of the symbol duration of the PSSCH being 6 and the numberof DMRSs being 2.

In step S2430, the first device 100 may transmit the DMRS to the seconddevice 200 through the PSSCH. For example, the first device 100 maytransmit the DMRS mapped onto resources related to the PSSCH to thesecond device 200 through the PSSCH.

The above-described embodiment may be applied to various devices to bedescribed below. First, for example, the processor 102 of the firstdevice 100 may control the transceiver 106 to transmit to transmit a SCIincluding information related to the pattern of a DMRS to a seconddevice 200 through a PSCCH. And, for example, the processor 102 of thefirst device 100 may map a DMRS onto resources related to the PSSCHbased on the information related to the pattern of the DMRS and a lengthof a symbol duration of the PSSCH related to the PSCCH. And, forexample, the processor 102 of the first device 100 may control thetransceiver 106 to transmit the DMRS to the second device 200 throughthe PSSCH.

According to an embodiment of the present disclosure, a first deviceconfigured to perform wireless communication may be provided. Forexample, the first device may comprise: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers.For example, the one or more processors may execute the instructions to:transmit, to a second device through a physical sidelink control channel(PSCCH), a sidelink control information (SCI) including informationrelated to a pattern of a demodulation reference signal (DMRS), map aDMRS onto resources related to physical sidelink shared channel (PSSCH)based on the information related to the pattern of the DMRS and a lengthof a symbol duration of the PSSCH related to the PSCCH, and transmit, tothe second device through the PSSCH, the DMRS.

According to an embodiment of the present disclosure, an apparatusconfigured to control a first user equipment (UE) may be provided. Forexample, the apparatus may comprise: one or more processors; and one ormore memories operably connected to the one or more processors andstoring instructions. For example, the one or more processors mayexecute the instructions to: transmit, to a second UE through a physicalsidelink control channel (PSCCH), a sidelink control information (SCI)including information related to a pattern of a demodulation referencesignal (DMRS), map a DMRS onto resources related to physical sidelinkshared channel (PSSCH) based on the information related to the patternof the DMRS and a length of a symbol duration of the PSSCH related tothe PSCCH, and transmit, to the second UE through the PSSCH, the DMRS.

According to an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, cause a first device to:transmit, to a second device through a physical sidelink control channel(PSCCH), a sidelink control information (SCI) including informationrelated to a pattern of a demodulation reference signal (DMRS), map aDMRS onto resources related to physical sidelink shared channel (PSSCH)based on the information related to the pattern of the DMRS and a lengthof a symbol duration of the PSSCH related to the PSCCH, and transmit, tothe second device through the PSSCH, the DMRS.

Hereinafter, an apparatus to which various embodiments of the presentdisclosure can be applied will be described.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 25 shows a communication system 1, in accordance with an embodimentof the present disclosure.

Referring to FIG. 25, a communication system 1 to which variousembodiments of the present disclosure are applied includes wirelessdevices, Base Stations (BSs), and a network. Herein, the wirelessdevices represent devices performing communication using Radio AccessTechnology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE))and may be referred to as communication/radio/5G devices. The wirelessdevices may include, without being limited to, a robot 100 a, vehicles100 b-1 and 100 b-2, an eXtended Reality (XR) device 100 c, a hand-helddevice 100 d, a home appliance 100 e, an Internet of Things (IoT) device100 f, and an Artificial Intelligence (AI) device/server 400. Forexample, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous vehicle, and a vehicle capable ofperforming communication between vehicles. Herein, the vehicles mayinclude an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR devicemay include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented in the form of a Head-Mounted Device(HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, asmartphone, a computer, a wearable device, a home appliance device, adigital signage, a vehicle, a robot, etc. The hand-held device mayinclude a smartphone, a smartpad, a wearable device (e.g., a smartwatchor a smartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine. TheIoT device may include a sensor and a smartmeter. For example, the BSsand the network may be implemented as wireless devices and a specificwireless device 200 a may operate as a BS/network node with respect toother wireless devices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay, Integrated AccessBackhaul (IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 26 shows wireless devices, in accordance with an embodiment of thepresent disclosure.

Referring to FIG. 26, a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 25.

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 27 shows a signal process circuit for a transmission signal, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 27, a signal processing circuit 1000 may includescramblers 1010, modulators 1020, a layer mapper 1030, a precoder 1040,resource mappers 1050, and signal generators 1060. An operation/functionof FIG. 27 may be performed, without being limited to, the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 26. Hardwareelements of FIG. 27 may be implemented by the processors 102 and 202and/or the transceivers 106 and 206 of FIG. 26. For example, blocks 1010to 1060 may be implemented by the processors 102 and 202 of FIG. 26.Alternatively, the blocks 1010 to 1050 may be implemented by theprocessors 102 and 202 of FIG. 26 and the block 1060 may be implementedby the transceivers 106 and 206 of FIG. 26.

Codewords may be converted into radio signals via the signal processingcircuit 1000 of FIG. 27. Herein, the codewords are encoded bit sequencesof information blocks. The information blocks may include transportblocks (e.g., a UL-SCH transport block, a DL-SCH transport block). Theradio signals may be transmitted through various physical channels(e.g., a PUSCH and a PDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 1010. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 1020. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complexmodulation symbol sequences may be mapped to one or more transportlayers by the layer mapper 1030. Modulation symbols of each transportlayer may be mapped (precoded) to corresponding antenna port(s) by theprecoder 1040. Outputs z of the precoder 1040 may be obtained bymultiplying outputs y of the layer mapper 1030 by an N*M precodingmatrix W. Herein, N is the number of antenna ports and M is the numberof transport layers. The precoder 1040 may perform precoding afterperforming transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 1040 may perform precoding withoutperforming transform precoding.

The resource mappers 1050 may map modulation symbols of each antennaport to time-frequency resources. The time-frequency resources mayinclude a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMAsymbols) in the time domain and a plurality of subcarriers in thefrequency domain. The signal generators 1060 may generate radio signalsfrom the mapped modulation symbols and the generated radio signals maybe transmitted to other devices through each antenna. For this purpose,the signal generators 1060 may include Inverse Fast Fourier Transform(IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-AnalogConverters (DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures 1010 to 1060 of FIG. 27. For example, the wireless devices(e.g., 100 and 200 of FIG. 26) may receive radio signals from theexterior through the antenna ports/transceivers. The received radiosignals may be converted into baseband signals through signal restorers.To this end, the signal restorers may include frequency downlinkconverters, Analog-to-Digital Converters (ADCs), CP remover, and FastFourier Transform (FFT) modules. Next, the baseband signals may berestored to codewords through a resource demapping procedure, apostcoding procedure, a demodulation processor, and a descramblingprocedure. The codewords may be restored to original information blocksthrough decoding. Therefore, a signal processing circuit (notillustrated) for a reception signal may include signal restorers,resource demappers, a postcoder, demodulators, descramblers, anddecoders.

FIG. 28 shows another example of a wireless device, in accordance withan embodiment of the present disclosure. The wireless device may beimplemented in various forms according to a use-case/service (refer toFIG. 25).

Referring to FIG. 28, wireless devices 100 and 200 may correspond to thewireless devices 100 and 200 of FIG. 26 and may be configured by variouselements, components, units/portions, and/or modules. For example, eachof the wireless devices 100 and 200 may include a communication unit110, a control unit 120, a memory unit 130, and additional components140. The communication unit may include a communication circuit 112 andtransceiver(s) 114. For example, the communication circuit 112 mayinclude the one or more processors 102 and 202 and/or the one or morememories 104 and 204 of FIG. 26. For example, the transceiver(s) 114 mayinclude the one or more transceivers 106 and 206 and/or the one or moreantennas 108 and 208 of FIG. 26. The control unit 120 is electricallyconnected to the communication unit 110, the memory 130, and theadditional components 140 and controls overall operation of the wirelessdevices. For example, the control unit 120 may control anelectric/mechanical operation of the wireless device based onprograms/code/commands/information stored in the memory unit 130. Thecontrol unit 120 may transmit the information stored in the memory unit130 to the exterior (e.g., other communication devices) via thecommunication unit 110 through a wireless/wired interface or store, inthe memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 25), the vehicles (100 b-1 and 100 b-2 of FIG. 25), the XRdevice (100 c of FIG. 25), the hand-held device (100 d of FIG. 25), thehome appliance (100 e of FIG. 25), the IoT device (100 f of FIG. 25), adigital broadcast terminal, a hologram device, a public safety device,an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 25), the BSs (200 of FIG. 25), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 28, the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 28 will be described indetail with reference to the drawings.

FIG. 29 shows a hand-held device, in accordance with an embodiment ofthe present disclosure. The hand-held device may include a smartphone, asmartpad, a wearable device (e.g., a smartwatch or a smartglasses), or aportable computer (e.g., a notebook). The hand-held device may bereferred to as a mobile station (MS), a user terminal (UT), a MobileSubscriber Station (MSS), a Subscriber Station (SS), an Advanced MobileStation (AMS), or a Wireless Terminal (WT).

Referring to FIG. 29, a hand-held device 100 may include an antenna unit108, a communication unit 110, a control unit 120, a memory unit 130, apower supply unit 140 a, an interface unit 140 b, and an I/O unit 140 c.The antenna unit 108 may be configured as a part of the communicationunit 110. Blocks 110 to 130/140 a to 140 c correspond to the blocks 110to 130/140 of FIG. 28, respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

FIG. 30 shows a vehicle or an autonomous vehicle, in accordance with anembodiment of the present disclosure. The vehicle or autonomous vehiclemay be implemented by a mobile robot, a car, a train, a manned/unmannedAerial Vehicle (AV), a ship, etc.

Referring to FIG. 30, a vehicle or autonomous vehicle 100 may include anantenna unit 108, a communication unit 110, a control unit 120, adriving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, andan autonomous driving unit 140 d. The antenna unit 108 may be configuredas a part of the communication unit 110. The blocks 110/130/140 a to 140d correspond to the blocks 110/130/140 of FIG. 28, respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous vehicle 100. The control unit 120 may includean Electronic Control Unit (ECU). The driving unit 140 a may cause thevehicle or the autonomous vehicle 100 to drive on a road. The drivingunit 140 a may include an engine, a motor, a powertrain, a wheel, abrake, a steering device, etc. The power supply unit 140 b may supplypower to the vehicle or the autonomous vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an InertialMeasurement Unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous vehicle 100 may movealong the autonomous driving path according to the driving plan (e.g.,speed/direction control). In the middle of autonomous driving, thecommunication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous vehicles and provide the predicted traffic information datato the vehicles or the autonomous vehicles.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod.

1. A method for performing wireless communication by a first device, themethod comprising: selecting a synchronization source based on asidelink synchronization priority, wherein the synchronization sourceincludes at least one of a global navigation satellite system (GNSS), abase station, or a terminal; obtaining synchronization based on thesynchronization source; transmitting, to a second device, asidelink-synchronization signal block (S-SSB) block based on thesynchronization, wherein the S-SSB block may include a sidelink primarysynchronization signal (S-PSS), a sidelink secondary synchronizationsignal (S-SSS), and a physical sidelink broadcast channel (PSBCH);transmitting, to the second device, information related to a pattern ofa physical sidelink shared channel demodulation reference signal (PSSCHDMRS) for decoding a PSSCH through a sidelink control information (SCI)on a physical sidelink control channel (PSCCH); mapping the PSSCH DMRSto time resources related to the PSSCH based on the information relatedto the pattern of the PSSCH DMRS and a duration of time resourcesscheduled for transmission of the PSSCH related to the PSCCH; andtransmitting, to the second device through the PSSCH, the PSSCH DMRS. 2.The method of claim 1, wherein the information related to the pattern ofthe PSSCH DMRS includes information on the number of PSSCH DMRSs, andwherein a first PSSCH DMRS is mapped to a second symbol in a slotrelated to the PSSCH based on the number of PSSCH DMRSs exceeding apre-configured threshold.
 3. The method of claim 2, wherein the firstsymbol in the slot related to the PSSCH includes an automatic gaincontrol (AGC) symbol.
 4. The method of claim 2, wherein frequencydivision multiplexing (FDM) is performed on resources related to thePSCCH and the resources related to the PSSCH.
 5. The method of claim 2,wherein the duration of the time resources scheduled for transmission ofthe PSSCH may be a symbol duration of the PSSCH, and wherein the PSSCHDMRS is mapped to the second symbol, a fifth symbol and an eighth symbolin the slot related to the PSSCH based on the length of the symbolduration of the PSSCH being 9 and the number of PSSCH DMRSs being
 3. 6.The method of claim 2, wherein the duration of the time resourcesscheduled for transmission of the PSSCH may be a symbol duration of thePSSCH, and wherein the PSSCH DMRS is mapped to the second symbol, asixth symbol, and a tenth symbol in the slot related to the PSSCH basedon the length of the symbol duration of the PSSCH being 11 and thenumber of DMRSs being
 3. 7. The method of claim 2, wherein the durationof the time resources scheduled for transmission of the PSSCH may be asymbol duration of the PSSCH, and wherein the PSSCH DMRS is mapped tothe second symbol, a seventh symbol, and a twelfth symbol in the slotrelated to the PSSCH based on the length of the symbol duration of thePSSCH being 13 and the number of PSSCH DMRSs being
 3. 8. The method ofclaim 2, wherein the duration of the time resources scheduled fortransmission of the PSSCH may be a symbol duration of the PSSCH, andwherein the PSSCH DMRS is mapped to the second symbol, a fifth symbol,an eighth and a eleventh symbol in the slot related to the PSSCH basedon the length of the symbol duration of the PSSCH being 13 and thenumber of PSSCH DMRSs being
 4. 9. The method of claim 1, wherein theinformation related to the pattern of the DMRS includes information forthe number of PSSCH DMRSs.
 10. The method of claim 9, wherein the firstPSSCH DMRS is mapped to symbols after a last symbol of the PSCCH basedon the number of PSSCH DMRSs being less than or equal to apre-configured threshold.
 11. The method of claim 9, wherein the firstPSSCH DMRS is mapped to a next symbol of the last symbol of the PSCCHbased on the number of PSSCH DMRSs being less than or equal to apre-configured threshold, and wherein time division multiplexing (TDM)is performed on resources related to the PSCCH and the resources relatedto the PSSCH.
 12. The method of claim 9 wherein the PSSCH DMRS is mappedto a fourth symbol and a ninth in the slot related to the PSSCH based onthe length of the symbol duration of the PSSCH being 9 and the number ofPSSCH DMRSs being
 2. 13. The method of claim 9, wherein the PSSCH DMRSis mapped to the second symbol and a sixth symbol in the slot related tothe PSSCH based on the length of the symbol duration of the PSSCH being6 and the number of PSSCH DMRSs being
 2. 14. A first device forperforming wireless communication, the first device comprising: one ormore memories storing instructions; one or more transceivers; and one ormore processors connected to the one or more memories and the one ormore transceivers, wherein the one or more processors execute theinstructions to: select a synchronization source based on a sidelinksynchronization priority, wherein the synchronization source includes atleast one of a global navigation satellite system (GNSS), a basestation, or a terminal, obtain synchronization based on thesynchronization source, transmit, to a second device, asidelink-synchronization signal block (S-SSB) block based on thesynchronization, wherein the S-SSB block may include a sidelink primarysynchronization signal (S-PSS), a sidelink secondary synchronizationsignal (S-SSS), and a physical sidelink broadcast channel (PSBCH),transmit, to the second device, information related to a pattern of aphysical sidelink shared channel demodulation reference signal (PSSCHDMRS) for decoding a PSSCH through a sidelink control information (SCI)on a physical sidelink control channel (PSCCH), map the PSSCH DMRS totime resources related to the PSSCH based on the information related tothe pattern of the PSSCH DMRS and a duration of time resources scheduledfor transmission of the PSSCH related to the PSCCH, transmit, to thesecond device through the PSSCH, the PSSCH DMRS.
 15. An deviceconfigured to control a first user equipment (UE), the devicecomprising: one or more processors; and one or more memories beingoperably connectable to the one or more processors and storinginstructions, wherein the one or more processors execute theinstructions to: select a synchronization source based on a sidelinksynchronization priority, wherein the synchronization source includes atleast one of a global navigation satellite system (GNSS), a basestation, or a terminal, obtain synchronization based on thesynchronization source, transmit, to a second UE, asidelink-synchronization signal block (S-SSB) block based on thesynchronization, wherein the S-SSB block may include a sidelink primarysynchronization signal (S-PSS), a sidelink secondary synchronizationsignal (S-SSS), and a physical sidelink broadcast channel (PSBCH),transmit, to the second UE, information related to a pattern of aphysical sidelink shared channel demodulation reference signal (PSSCHDMRS) for decoding a PSSCH through a sidelink control information (SCI)on a physical sidelink control channel (PSCCH), map the PSSCH DMRS totime resources related to the PSSCH based on the information related tothe pattern of the PSSCH DMRS and a duration of time resources scheduledfor transmission of the PSSCH related to the PSCCH, transmit, to thesecond UE through the PSSCH, the PSSCH DMRS. 16-20. (canceled)